Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)

Apparently, the style needs to be agreed upon first.

llvm-svn: 240390
diff --git a/llvm/lib/Support/MathExtras.cpp b/llvm/lib/Support/MathExtras.cpp
index 9265a43..ba09245 100644
--- a/llvm/lib/Support/MathExtras.cpp
+++ b/llvm/lib/Support/MathExtras.cpp
@@ -29,4 +29,4 @@
   const float huge_valf = HUGE_VALF;
 #endif
 
-} // namespace llvm
+}