[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/javastatic/intersectionOverrideOnStaticKJJ.kt

@@ -0,0 +1,38 @@
+// FIR_IDENTICAL
+// TARGET_BACKEND: JVM
+
+// FILE: Java1.java
+
+public class Java1 {
+    public static int a = 2;
+    public static void foo(Object t) { }
+    public static Object bar() {
+        return null;
+    }
+}
+// FILE: Java2.java
+public interface Java2 {
+    public int a = 2;
+    public void foo(String t);
+    public String bar();
+}
+
+// FILE: 1.kt
+
+abstract class B : Java1(), Java2
+
+class C : Java1(), Java2 {
+    override fun foo(t: String) {}
+
+    override fun bar(): String {
+        return ""
+    }
+}
+
+fun test(b: B, c: C) {
+    val k: String = b.bar()
+    b.foo("")
+    b.foo(null)
+    val k2: String = c.bar()
+    c.foo("")
+}