[FIR2IR] Mute some tests due to captured type problems

compiler/testData/codegen/box/javaInterop/genericSamSmartcast.kt

@@ -1,3 +1,4 @@
+// IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
 // FILE: A.java
 public class A<T> {
@@ -11,6 +12,7 @@ public class A<T> {
 // FILE: test.kt
 fun f(x: Any): String {
     if (x is A<*>) {
+        // Fails in FIR due to inconsistent lambda argument type (Nothing? expected)
         return x.call { y: Any? -> "OK" }
     }
     return "Fail"