Move codegen tests on old language versions under oldLanguageVersions/

This directory is skipped in JVM IR test generator, so they won't show
up as failed anymore.

Note that only failing tests are moved to oldLanguageVersions/. Tests
which already pass are still being run. It may be useful not to break
them in case we _do_ need to support some pre-1.3 language feature
switches in JVM IR.

compiler/testData/codegen/box/controlStructures/forInArray/forInArrayWithArrayVarUpdatedInLoopBody12.kt

@@ -1,16 +0,0 @@
-// !LANGUAGE: -ProperForInArrayLoopRangeVariableAssignmentSemantic
-// IGNORE_BACKEND: NATIVE
-// IGNORE_BACKEND: JVM_IR
-// IGNORE_BACKEND: JS_IR
-// WITH_RUNTIME
-// IGNORE_BACKEND: JS
-
-fun box(): String {
-    var xs = intArrayOf(1, 2, 3)
-    var sum = 0
-    for (x in xs) {
-        sum = sum * 10 + x
-        xs = intArrayOf(4, 5)
-    }
-    return if (sum == 15) "OK" else "Fail: $sum"
-}