JVM IR: (Un)mute tests and add more tests for bridge generation

compiler/testData/codegen/box/bridges/fakeOverrideThroughGenericSuperclass.kt

@@ -0,0 +1,22 @@
+// IGNORE_BACKEND: JS_IR
+
+var result = "Fail"
+
+interface A<T> {
+    fun f(x: T) {
+        result = x.toString()
+    }
+}
+
+abstract class B1<T> : A<T>
+
+interface B2 {
+    fun f(x: String)
+}
+
+class C : B1<String>(), B2
+
+fun box(): String {
+    (C() as B2).f("OK")
+    return result
+}