[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/void/basicVoidOverride.kt

@@ -0,0 +1,25 @@
+// FIR_IDENTICAL
+// TARGET_BACKEND: JVM
+
+// FILE: Java1.java
+public class Java1 {
+    public Void foo(){
+        return null;
+    }
+}
+
+// FILE: 1.kt
+class A : Java1()
+
+class B : Java1() {
+    override fun foo(): Void {
+        return null!!
+    }
+}
+
+fun test() {
+    val k: Void? = A().foo()
+    val k2: Any = A().foo()
+    val k3: Void = B().foo()
+    val k4: Any = B().foo()
+}