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

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

@@ -0,0 +1,22 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+
+open class Base<T> {
+    open fun f(x: T): String {
+        return "Fail"
+    }
+}
+
+abstract class Derived : Base<String>() {
+    abstract override fun f(x: String): String
+}
+
+class Implementation : Derived() {
+    override fun f(x: String): String {
+        return x
+    }
+}
+
+fun box(): String {
+    val base = Implementation() as Base<String>
+    return base.f("OK")
+}

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
+}