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/topLevelMembersInTwoFiles/a.kt

@@ -0,0 +1,12 @@
+package test
+
+fun foo() {
+    bar(5)
+    baz()
+}
+
+fun baz() {
+}
+
+val prop1 = ""
+val prop2 = prop1