[FE 1.0] Drop ArrayLiteralsInAnnotations feature

This feature was introduced in 1.2, so now it's stable part of language
  and we can drop support of disabling it

compiler/testData/diagnostics/tests/collectionLiterals/defaultValuesInAnnotation.kt

@@ -1,5 +1,3 @@
-// !LANGUAGE: +ArrayLiteralsInAnnotations
-
 annotation class Foo(
         val a: Array<String> = ["/"],
         val b: Array<String> = [],