Test data split between compiledJava tests and compiledKotlin tests

Basically, this commit splits test data from the from java-txt-kt to two pairs java-txt and kt-txt.
This commit leads to some duplication in test data.
This is temporary: in the platform types branch the test data for LoadJava tests will be changed dramatically, so duplication will go away

compiler/testData/loadJava/compiledJava/kotlinSignature/error/WrongFieldMutability.txt

@@ -0,0 +1,7 @@
+package test
+
+public open class WrongFieldMutability {
+    public constructor WrongFieldMutability()
+    public final val fooFinal: kotlin.String? = "Test"
+    public final var fooNotFinal: kotlin.String?
+}