Add tests for obsolete codegen issues

#KT-8203 Obsolete
 #KT-15950 Obsolete

compiler/testData/codegen/box/callableReference/bound/arrayGetIntrinsic.kt

@@ -0,0 +1,3 @@
+fun box(): String {
+    return if ((arrayOf(1, 2, 3)::get)(1) == 2) "OK" else "Fail"
+}

compiler/testData/codegen/box/defaultArguments/useThisInLambda.kt

@@ -0,0 +1,7 @@
+class X {
+    fun g(x: () -> Boolean = { super.equals(this) }) = x()
+}
+
+fun box(): String {
+    return if (X().g()) "OK" else "Fail: false"
+}