Remove codegen tests with Java, move testData to boxWithJava/

There'll be a single generated test class like
BlackBoxCodegenTestGenerated

compiler/testData/codegen/boxWithJava/enum/simpleJavaInnerEnum.java

@@ -4,4 +4,4 @@ public class simpleJavaInnerEnum {
     public enum MyEnum {
         A;
     }
-}
+}

compiler/testData/codegen/boxWithJava/functions/removeInIterator.java

@@ -2,4 +2,4 @@ public class removeInIterator {
     public static void bar(java.util.Iterator<Integer> it) {
         it.remove();
     }
-}
+}

compiler/testData/codegen/boxWithJava/functions/removeInIterator.kt

@@ -10,4 +10,4 @@ fun box() : String {
             return "OK"
     }
     return "fail"
-}
+}

compiler/testData/codegen/boxWithJava/staticFun/classWithNestedEnum.java

@@ -1,6 +1,6 @@
 package test;
 
-public class noClassObjectForJavaClass {
+public class classWithNestedEnum {
     public enum E { ENTRY }
     
     public static String foo() { return "OK"; }

compiler/testData/codegen/boxWithJava/staticFun/classWithNestedEnum.kt

@@ -0,0 +1,5 @@
+package test
+
+fun box(): String {
+    return classWithNestedEnum.foo()!!
+}

compiler/testData/codegen/stdlib/noClassObjectForJavaClass.kt

@@ -1,5 +0,0 @@
-package test
-
-fun box(): String {
-    return noClassObjectForJavaClass.foo()!!
-}