[JS TESTS] Remove LANGUAGE_VERSION directive

Some of them are not necessary at all, others can be replaced with
`!LANGUAGE` directive with exclusion of corresponding features.

js/js.translator/testData/box/expression/function/varargUInt.kt

@@ -1,4 +1,3 @@
-// LANGUAGE_VERSION: 1.5
 // KJS_WITH_FULL_RUNTIME
 // EXPECTED_REACHABLE_NODES: 1787
 package foo

js/js.translator/testData/box/inlineMultiModule/inlineMemberFunWithLambda.kt

@@ -1,6 +1,5 @@
 // IGNORE_BACKEND: JS_IR_ES6
 // EXPECTED_REACHABLE_NODES: 1397
-// LANGUAGE_VERSION: 1.2
 // MODULE: lib
 // FILE: lib.kt
 open class C {

js/js.translator/testData/box/operatorOverloading/usingModInCaseModAssignNotAvailable.kt

@@ -1,4 +1,4 @@
-// LANGUAGE_VERSION: 1.1
+// !LANGUAGE: -ProhibitOperatorMod
 // EXPECTED_REACHABLE_NODES: 1284
 package foo
 

js/js.translator/testData/box/propertyAccess/simpleLateInitIsInitialized.kt

@@ -1,5 +1,4 @@
 // EXPECTED_REACHABLE_NODES: 1294
-// LANGUAGE_VERSION: 1.2
 // WITH_RUNTIME
 
 fun deinitialize(foo: dynamic) {

js/js.translator/testData/box/reflection/primitives-11.kt

@@ -1,5 +1,5 @@
 // EXPECTED_REACHABLE_NODES: 1290
-// LANGUAGE_VERSION: 1.1
+// !LANGUAGE: -ProhibitGenericArrayClassLiteral
 import kotlin.reflect.KClass
 
 fun box(): String {