K2: add checker detecting protected Java field shadowed by a property

compiler/testData/diagnostics/tests/javaFieldKotlinPropertyJavaPackagePrivateField.kt

@@ -0,0 +1,27 @@
+// FILE: A.java
+
+package base;
+
+public class A {
+    String f = "OK";
+}
+
+// FILE: B.kt
+
+package base
+
+open class B : A() {
+    private val f = "FAIL"
+}
+
+// FILE: C.java
+
+import base.B;
+
+public class C extends B {}
+
+// FILE: test.kt
+
+fun box(): String {
+    return C().<!INVISIBLE_MEMBER!>f<!>
+}