[Test] KT-61360: add tests for the IrFakeOverrideBuilder

Add tests for fake overrides with focus on java interoperability

Co-authored-by: Aleksandra Arsenteva <aleksandra.arsenteva@jetbrains.com>

compiler/testData/ir/irText/fakeOverrides/generics/genericMethodOverrideOnKJJ.kt

@@ -0,0 +1,74 @@
+// TARGET_BACKEND: JVM
+// WITH_STDLIB
+
+// FILE: Java1.java
+public class Java1 {
+    public <T> void foo(T a) { }
+    public <T> T bar() {
+        return null;
+    }
+}
+
+// FILE: Java2.java
+public class Java2 extends Java1 { }
+
+// FILE: Java3.java
+public class Java3 extends Java1   {
+    @Override
+    public <T> void foo(T a) { }
+    @Override
+    public <T> T bar() {
+        return null;
+    }
+}
+
+// FILE: 1.kt
+abstract class A : Java2()    // Kotlin ← Java1 ← Java2
+
+class B : A() {
+    override fun <T> bar(): T {
+        return null!!
+    }
+    override fun <T> foo(a: T) { }
+}
+
+class C : Java3()   //Kotlin ← Java1(override) ← Java2
+
+class D : Java1() {
+    override fun <T : Any?> bar(): T {
+        return null!!
+    }
+    override fun <T> foo(a: T) {
+        println(a)
+    }
+}
+
+fun test(a: A, b: B, c: C, d: D) {
+    val k: Int = a.bar<Int>()
+    val k3: Any = a.bar()
+    a.foo(1)
+    a.foo(null)
+    a.foo<Int?>(null)
+    a.foo(listOf(null))
+
+    val k5: Int? = b.bar<Int?>()
+    val k6: Any = b.bar<Any>()
+    b.foo(1)
+    b.foo(null)
+    b.foo<Int?>(null)
+    b.foo(listOf(null))
+
+    val k7: Int? = c.bar<Int?>()
+    val k8: Any = c.bar<Any>()
+    c.foo(1)
+    c.foo(null)
+    c.foo<Int?>(null)
+    c.foo(listOf(null))
+
+    val k9: Int? = d.bar<Int?>()
+    val k10: Any = d.bar<Any>()
+    d.foo(1)
+    d.foo(null)
+    d.foo<Int?>(null)
+    d.foo(listOf(null))
+}