Massive test suite cleanup to stop everyone from manually having to compute "mydir" inside each test case. 

This has led to many test suite failures because of copy and paste where new test cases were based off of other test cases and the "mydir" variable wasn't updated.

Now you can call your superclasses "compute_mydir()" function with "__file__" as the sole argument and the relative path will be computed for you. 

llvm-svn: 196985
diff --git a/lldb/test/macosx/order/TestOrderFile.py b/lldb/test/macosx/order/TestOrderFile.py
index 393dbb4..5ee9242 100644
--- a/lldb/test/macosx/order/TestOrderFile.py
+++ b/lldb/test/macosx/order/TestOrderFile.py
@@ -10,7 +10,7 @@
 
 class OrderFileTestCase(TestBase):
 
-    mydir = os.path.join("macosx", "order")
+    mydir = TestBase.compute_mydir(__file__)
 
     @unittest2.skipUnless(sys.platform.startswith("darwin"), "requires Darwin")
     @dsym_test