…election

…amework after options are already set

- Also provide each test framework with a display name property for user-facing references.

… set is blocked elsewhere

- Add comment explaining why.
- Add tests to ensure behavior remains correct.

…accessed; check this when changing framework in a suite

- We need to check not just when changing the test framework within a test task, but when changing the test framework for a suite
if the associated test tasks for that suite have had options accessed.  Otherwise, the test task will silently continue to use the options
and framework first configured without switching to the new ones.
- Create new test class to demonstrate misconfigurations of options.

- Consolidate options-related tests.

- Remove margin bar in multiline strings.
- Make naming of migrated method consistent.
- Remove extraneous comments.

…ite in error message if attempt fails due to test options already being accessed

# Conflicts:
#	subprojects/plugins/src/main/java/org/gradle/api/plugins/jvm/internal/DefaultJvmTestSuite.java
#	subprojects/testing-jvm/src/main/java/org/gradle/api/internal/tasks/testing/TestFramework.java
#	subprojects/testing-jvm/src/main/java/org/gradle/api/internal/tasks/testing/junit/JUnitTestFramework.java
#	subprojects/testing-jvm/src/main/java/org/gradle/api/internal/tasks/testing/junitplatform/JUnitPlatformTestFramework.java
#	subprojects/testing-jvm/src/main/java/org/gradle/api/internal/tasks/testing/testng/TestNGTestFramework.java

…in either order