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/classSignatureUnchanged/build.log

@@ -0,0 +1,6 @@
+Cleaning output files:
+out/production/module/test/Klass.class
+End of files
+Compiling files:
+src/class.kt
+End of files

jps-plugin/testData/incremental/pureKotlin/classSignatureUnchanged/class.kt

@@ -0,0 +1,7 @@
+package test
+
+class Klass {
+    fun foo() = ":)"
+
+    fun bar() = ":("
+}

jps-plugin/testData/incremental/pureKotlin/classSignatureUnchanged/class.kt.new

@@ -0,0 +1,8 @@
+package test
+
+// swapped functions
+class Klass {
+    fun bar() = ":("
+
+    fun foo() = ":)"
+}

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

@@ -0,0 +1,6 @@
+package test
+
+fun usage(a: Klass) {
+    a.foo()
+    a.bar()
+}