Add tests for obsolete issues

#KT-4628 Obsolete
 #KT-3897 Obsolete
 #KT-3898 Obsolete
 #KT-7523 Obsolete

compiler/testData/diagnostics/tests/j+k/brokenCode/classDuplicates.kt

@@ -0,0 +1,13 @@
+// FILE: Hello.kt
+private class Hello()
+{
+    val a = 4
+}
+
+fun test() {
+    // no exception is thrown (see KT-3897)
+    Hello().a
+}
+
+// FILE: Hello.java
+public class Hello {}

compiler/testData/diagnostics/tests/j+k/brokenCode/classDuplicates.txt

@@ -0,0 +1,18 @@
+package
+
+public fun test(): kotlin.Unit
+
+private final class Hello {
+    public constructor Hello()
+    public final val a: kotlin.Int = 4
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public open class Hello {
+    public constructor Hello()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/j+k/brokenCode/fieldDuplicates.kt

@@ -0,0 +1,13 @@
+// FILE: A.java
+
+public class A {
+    public String foo;
+    public String foo = "";
+}
+
+// FILE: main.kt
+
+fun foo() {
+    // no exception is thrown (see KT-3898)
+    A().foo
+}

compiler/testData/diagnostics/tests/j+k/brokenCode/fieldDuplicates.txt

@@ -0,0 +1,11 @@
+package
+
+public fun foo(): kotlin.Unit
+
+public open class A {
+    public constructor A()
+    public final var foo: kotlin.String!
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}