Moved current incremental compiler test data into subdirectory.

Tweaked test generator to avoid creating test methods for parent directory of tests.

jps-plugin/testData/incremental/pureKotlin/accessingFunctionsViaPackagePart/usage.kt

@@ -0,0 +1,5 @@
+package test
+
+fun main(args: Array<String>) {
+    println(a() + b() + other.other())
+}