Rename test data folder according to the new test naming convention.

compiler/testData/loadJavaCustom/staticFinal/expected.txt

@@ -0,0 +1,3 @@
+namespace test
+
+public final val foo: jet.String

compiler/testData/loadJavaCustom/staticFinal/test.java

@@ -0,0 +1,3 @@
+public class test {
+    public static final String foo = "aaa";
+}