Specify JVM target backend for other java related tests

compiler/testData/codegen/box/builtinStubMethods/IteratorWithRemove.kt

@@ -1,6 +1,4 @@
-// IGNORE_BACKEND: JS_IR
-// TODO: muted automatically, investigate should it be ran for JS or not
-// IGNORE_BACKEND: JS, NATIVE
+// TARGET_BACKEND: JVM
 
 class MyIterator<T>(val v: T): Iterator<T> {
     override fun next(): T = v