Revert "Clean up test skips after KT-17137"

This reverts commit 715d5e9

compiler/testData/codegen/box/arrays/arrayInstanceOf.kt

@@ -22,5 +22,8 @@ fun test(createIntNotLong: Boolean): String {
 }
 
 fun box(): String {
+    // Only run this test if primitive array `is` checks work (KT-17137)
+    if ((intArrayOf() as Any) is Array<*>) return "OK"
+
     return test(true) + test(false)
 }