land David Blaikie's patch to de-constify Type, with a few tweaks.

llvm-svn: 135375
diff --git a/llvm/unittests/ADT/SmallVectorTest.cpp b/llvm/unittests/ADT/SmallVectorTest.cpp
index 0d3535d..d5bfe76 100644
--- a/llvm/unittests/ADT/SmallVectorTest.cpp
+++ b/llvm/unittests/ADT/SmallVectorTest.cpp
@@ -383,7 +383,7 @@
 
 // Constant vector tests.
 TEST_F(SmallVectorTest, ConstVectorTest) {
-  const VectorType constVector;
+  VectorType constVector;
 
   EXPECT_EQ(0u, constVector.size());
   EXPECT_TRUE(constVector.empty());