[TEST] Migrate AbstractDiagnosticsWithExplicitApi to new test runners

compiler/testData/diagnostics/tests/testsWithExplicitApi/mustBeEffectivelyPublic.kt

@@ -0,0 +1,23 @@
+// FIR_IDENTICAL
+// SKIP_TXT
+
+private class Foo {
+    fun method() {}
+}
+
+public interface I {
+    public fun bar()
+}
+
+public fun f() {
+    val i = object : I {
+        internal var foo = 0
+        override fun bar() {}
+    }
+    i.foo = 1
+
+    class LocalClass {
+        internal var foo = 0
+    }
+    LocalClass().foo = 1
+}