K2: add tests to confirm current behavior of KT-65679 examples

compiler/testData/diagnostics/tests/j+k/internalClash.fir.kt

@@ -0,0 +1,17 @@
+// FILE: B.java
+
+public class B extends A {}
+
+// FILE: box.kt
+
+open class A {
+    internal open val a: String = "Fail"
+}
+
+class C : B() {
+    internal val <!VIRTUAL_MEMBER_HIDDEN!>a<!>: String = "OK"
+}
+
+fun box(): String {
+    return C().a
+}

compiler/testData/diagnostics/tests/j+k/internalClash.kt

@@ -0,0 +1,17 @@
+// FILE: B.java
+
+public class B extends A {}
+
+// FILE: box.kt
+
+open class A {
+    internal open val a: String = "Fail"
+}
+
+class C : B() {
+    internal val a: String = "OK"
+}
+
+fun box(): String {
+    return C().a
+}

compiler/testData/diagnostics/tests/j+k/internalClash2.fir.kt

@@ -0,0 +1,15 @@
+// FILE: B.java
+
+public class B extends A {}
+
+// FILE: box.kt
+
+open class A {
+    internal open val a: String = "OK"
+}
+
+class C : B()
+
+fun box(): String {
+    return C().a
+}

compiler/testData/diagnostics/tests/j+k/internalClash2.kt

@@ -0,0 +1,15 @@
+// FILE: B.java
+
+public class B extends A {}
+
+// FILE: box.kt
+
+open class A {
+    internal open val a: String = "OK"
+}
+
+class C : B()
+
+fun box(): String {
+    return C().<!INVISIBLE_MEMBER!>a<!>
+}