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/AddingNullability.java

@@ -0,0 +1,12 @@
+package test;
+
+import jet.runtime.typeinfo.KotlinSignature;
+import org.jetbrains.jet.jvm.compiler.annotation.ExpectLoadError;
+
+public class AddingNullability {
+    @ExpectLoadError("Auto type 'kotlin.Int' is not-null, while type in alternative signature is nullable: 'Int?'")
+    @KotlinSignature("fun foo() : Int?")
+    public int foo() {
+        throw new UnsupportedOperationException();
+    }
+}