fix(es/minifier): Fix code for dropping unreachable statements (#6429)

**Related issue:**

 - Closes #6405.

Author: kdy1

crates/swc_ecma_minifier/src/compress/pure/dead_code.rs

@@ -269,15 +269,7 @@ impl Pure<'_> {
                 );
             }
 
-            match stmts[idx].as_stmt() {
-                Some(Stmt::Return(ReturnStmt { arg: None, .. })) => {
-                    // Exclude return
-                    new_stmts.extend(stmts.drain(..idx));
-                }
-                _ => {
-                    new_stmts.extend(stmts.drain(..=idx));
-                }
-            }
+            new_stmts.extend(stmts.drain(..=idx));
 
             new_stmts.extend(hoisted_fns);
 

crates/swc_ecma_minifier/tests/pass-1/issue-6405/1/input.js

@@ -0,0 +1,14 @@
+export const fn = () => {
+    let val;
+
+    if (!val) {
+        return undefined;
+        // works as expected if comment out below line
+        throw new Error('first');
+    }
+
+    if (val.a?.b !== true) { // Uncaught TypeError: Cannot read properties of undefined (reading 'a')
+        throw new Error('second');
+    }
+    return val;
+}

crates/swc_ecma_minifier/tests/pass-1/issue-6405/1/output.js

@@ -0,0 +1,7 @@
+export const fn = ()=>{
+    let val;
+    if (!!val) {
+        if (val.a?.b !== !0) throw Error('second');
+        return val;
+    }
+};