Prepare test data for removal of separate test configurations for JDK 21

^KT-58765

Now that JDK 21 was released as stable, we can remove separate test
configurations for testing the compiler with JDK 21 and reintegrate
the corresponding test data into standard test configurations.

compiler/testData/diagnostics/tests/testsWithJava21/noFalsePositiveAbstractToArray.kt

@@ -0,0 +1,48 @@
+// FIR_IDENTICAL
+// ISSUE: KT-60770
+
+// Should be no ABSTRACT_MEMBER_NOT_IMPLEMENTED
+class B<F> : List<F> {
+    override val size: Int
+        get() = throw UnsupportedOperationException()
+
+    override fun contains(element: F): Boolean {
+        throw UnsupportedOperationException()
+    }
+
+    override fun containsAll(elements: Collection<F>): Boolean {
+        throw UnsupportedOperationException()
+    }
+
+    override fun get(index: Int): F {
+        throw UnsupportedOperationException()
+    }
+
+    override fun indexOf(element: F): Int {
+        throw UnsupportedOperationException()
+    }
+
+    override fun isEmpty(): Boolean {
+        throw UnsupportedOperationException()
+    }
+
+    override fun iterator(): Iterator<F> {
+        throw UnsupportedOperationException()
+    }
+
+    override fun lastIndexOf(element: F): Int {
+        throw UnsupportedOperationException()
+    }
+
+    override fun listIterator(): ListIterator<F> {
+        throw UnsupportedOperationException()
+    }
+
+    override fun listIterator(index: Int): ListIterator<F> {
+        throw UnsupportedOperationException()
+    }
+
+    override fun subList(fromIndex: Int, toIndex: Int): List<F> {
+        throw UnsupportedOperationException()
+    }
+}