Warn on for-in-array range variable assignment in loop body

According to KT-21354, this should be a warning in 1.2 and before, and
no warning (with changed semantics) in 1.3 and later.
NB there are some false positives in this check.

 #KT-21354 In Progress
 #KT-21321 In Progress

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -75,6 +75,7 @@ enum class LanguageFeature(
     RestrictionOfWrongAnnotationsWithUseSiteTargetsOnTypes(KOTLIN_1_3),
     ProhibitInnerClassesOfGenericClassExtendingThrowable(KOTLIN_1_3),
     ProperVisibilityForCompanionObjectInstanceField(KOTLIN_1_3),
+    ProperForInArrayLoopRangeVariableAssignmentSemantic(KOTLIN_1_3),
 
     StrictJavaNullabilityAssertions(sinceVersion = null, defaultState = State.DISABLED),