Minor: use ".touch" extension instead of ".new" in incremental compilation tests when it possible

Original commit: d9b67ae0ef

jps/jps-plugin/testData/incremental/custom/kotlinConstantUnchangedUsedInJava/const.kt.new

@@ -1,7 +0,0 @@
-package test
-
-class Klass {
-    companion object {
-        val CONST = "bar"
-    }
-}