Revert "[PowerPC] Improve consistency in use of __ppc__, __powerpc__, etc."

This reverts commit r187248. It broke many bots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187254 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/ADT/BitVectorTest.cpp b/unittests/ADT/BitVectorTest.cpp
index 4d3223e..d7cde89 100644
--- a/unittests/ADT/BitVectorTest.cpp
+++ b/unittests/ADT/BitVectorTest.cpp
@@ -8,7 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 // Some of these tests fail on PowerPC for unknown reasons.
-#if !defined(__ppc__) && !defined(__powerpc__)
+#ifndef __ppc__
 
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/SmallBitVector.h"