[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/java21/sequenceMapIntersectionOverrideKJJ.fir.kt.txt

@@ -0,0 +1,31 @@
+abstract class A : HashMap<Int, Int>, SequencedMap<Int, Int> {
+  constructor() /* primary */ {
+    super/*HashMap*/<Int, Int>()
+    /* <init>() */
+
+  }
+
+}
+
+class B : HashMap<Int, Int>, SequencedMap<Int, Int> {
+  constructor() /* primary */ {
+    super/*HashMap*/<Int, Int>()
+    /* <init>() */
+
+  }
+
+  override fun reversed(): SequencedMap<Int, Int> {
+    return CHECK_NOT_NULL<Nothing>(arg0 = null)
+  }
+
+}
+
+fun test(a: A, b: B) {
+  a.<get-size>() /*~> Unit */
+  a.putLast(p0 = null, p1 = 1) /*~> Unit */
+  a.putLast(p0 = 2, p1 = null) /*~> Unit */
+  a.firstEntry() /*~> Unit */
+  a.lastEntry() /*~> Unit */
+  a.reversed() /*~> Unit */
+  b.reversed() /*~> Unit */
+}