FIR: Unmute passing blackbox tests

compiler/testData/codegen/box/delegation/delegationWithPrivateConstructor.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 class MyObject private constructor(val delegate: Interface) : Interface by delegate {
     constructor() : this(Delegate())
 }
@@ -15,4 +14,4 @@ private interface Interface {
 
 fun box(): String {
     return MyObject().greet()
-}
+}

compiler/testData/codegen/box/delegation/withDefaultParameters.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
-
 var log = ""
 fun log(a: String) {
     log += a + ";"
@@ -57,4 +55,4 @@ fun box(): String {
     if (log != "C.foo(2);C.foo(1);[2] object:C.foo(2);[2] object:C.foo(1);") return "fail2: $log"
 
     return "OK"
-}
+}