Avoid reflection on java.util.concurrent internals during tests.

Under modern JDKs, it will fail.

This lets us remove one of our `--add-opens` lines. (I haven't looked into [the others](#5801 (comment)).)

Example failure:

```
java.lang.reflect.InaccessibleObjectException: Unable to make protected final java.lang.Thread java.util.concurrent.locks.AbstractOwnableSynchronizer.getExclusiveOwnerThread() accessible: module java.base does not "opens java.util.concurrent.locks" to unnamed module @5ba184fc; did you mean --add-opens=java.base/java.util.concurrent.locks=ALL-UNNAMED
	at java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:348)
	at java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:280)
	at java.lang.reflect.Method.checkCanSetAccessible(Method.java:198)
	at java.lang.reflect.Method.setAccessible(Method.java:192)
	at com.google.common.util.concurrent.InterruptibleTaskTest.testInterruptIsSlow(InterruptibleTaskTest.java:160)
```

Relevant to #5801

RELNOTES=n/a
PiperOrigin-RevId: 469500716

android/guava-tests/test/com/google/common/util/concurrent/InterruptibleTaskTest.java

@@ -17,11 +17,10 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
-import java.lang.reflect.Method;
+import com.google.common.util.concurrent.InterruptibleTask.Blocker;
 import java.nio.channels.spi.AbstractInterruptibleChannel;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.locks.AbstractOwnableSynchronizer;
 import java.util.concurrent.locks.LockSupport;
 import junit.framework.TestCase;
 
@@ -152,12 +151,8 @@ public void run() {
     // waiting for the slow interrupting thread to complete Thread.interrupt
     awaitBlockedOnInstanceOf(runner, InterruptibleTask.Blocker.class);
 
-    Object blocker = LockSupport.getBlocker(runner);
-    assertThat(blocker).isInstanceOf(AbstractOwnableSynchronizer.class);
-    Method getExclusiveOwnerThread =
-        AbstractOwnableSynchronizer.class.getDeclaredMethod("getExclusiveOwnerThread");
-    getExclusiveOwnerThread.setAccessible(true);
-    Thread owner = (Thread) getExclusiveOwnerThread.invoke(blocker);
+    Blocker blocker = (Blocker) LockSupport.getBlocker(runner);
+    Thread owner = blocker.getOwner();
     assertThat(owner).isSameInstanceAs(interrupter);
 
     slowChannel.exitClose.countDown(); // release the interrupter

android/guava/src/com/google/common/util/concurrent/InterruptibleTask.java

@@ -233,6 +233,11 @@ private void setOwner(Thread thread) {
       super.setExclusiveOwnerThread(thread);
     }
 
+    @VisibleForTesting
+    Thread getOwner() {
+      return super.getExclusiveOwnerThread();
+    }
+
     @Override
     public String toString() {
       return task.toString();

android/pom.xml

@@ -425,7 +425,7 @@
       </activation>
       <properties>
         <!--
-            Some tests need reflective access to the internals of these packages. It is ony the
+            Some tests need reflective access to the internals of these packages. It is only the
             tests themselves and not the code being tested that needs that access, though there's no
             obvious way to ensure that.
 
@@ -435,7 +435,6 @@
         <test.add.opens>
           --add-opens java.base/java.lang=ALL-UNNAMED
           --add-opens java.base/java.util=ALL-UNNAMED
-          --add-opens java.base/java.util.concurrent.locks=ALL-UNNAMED
           --add-opens java.base/sun.security.jca=ALL-UNNAMED
         </test.add.opens>
       </properties>

guava-tests/test/com/google/common/util/concurrent/InterruptibleTaskTest.java

@@ -17,11 +17,10 @@
 
 import static com.google.common.truth.Truth.assertThat;
 
-import java.lang.reflect.Method;
+import com.google.common.util.concurrent.InterruptibleTask.Blocker;
 import java.nio.channels.spi.AbstractInterruptibleChannel;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.locks.AbstractOwnableSynchronizer;
 import java.util.concurrent.locks.LockSupport;
 import junit.framework.TestCase;
 
@@ -152,12 +151,8 @@ public void run() {
     // waiting for the slow interrupting thread to complete Thread.interrupt
     awaitBlockedOnInstanceOf(runner, InterruptibleTask.Blocker.class);
 
-    Object blocker = LockSupport.getBlocker(runner);
-    assertThat(blocker).isInstanceOf(AbstractOwnableSynchronizer.class);
-    Method getExclusiveOwnerThread =
-        AbstractOwnableSynchronizer.class.getDeclaredMethod("getExclusiveOwnerThread");
-    getExclusiveOwnerThread.setAccessible(true);
-    Thread owner = (Thread) getExclusiveOwnerThread.invoke(blocker);
+    Blocker blocker = (Blocker) LockSupport.getBlocker(runner);
+    Thread owner = blocker.getOwner();
     assertThat(owner).isSameInstanceAs(interrupter);
 
     slowChannel.exitClose.countDown(); // release the interrupter

guava/src/com/google/common/util/concurrent/InterruptibleTask.java

@@ -233,6 +233,11 @@ private void setOwner(Thread thread) {
       super.setExclusiveOwnerThread(thread);
     }
 
+    @VisibleForTesting
+    Thread getOwner() {
+      return super.getExclusiveOwnerThread();
+    }
+
     @Override
     public String toString() {
       return task.toString();

pom.xml

@@ -432,7 +432,7 @@
       </activation>
       <properties>
         <!--
-            Some tests need reflective access to the internals of these packages. It is ony the
+            Some tests need reflective access to the internals of these packages. It is only the
             tests themselves and not the code being tested that needs that access, though there's no
             obvious way to ensure that.
 
@@ -442,7 +442,6 @@
         <test.add.opens>
           --add-opens java.base/java.lang=ALL-UNNAMED
           --add-opens java.base/java.util=ALL-UNNAMED
-          --add-opens java.base/java.util.concurrent.locks=ALL-UNNAMED
           --add-opens java.base/sun.security.jca=ALL-UNNAMED
         </test.add.opens>
       </properties>