Misc typos fixes in ./lib folder

Summary: Found via `codespell -q 3 -I ../clang-whitelist.txt -L uint,importd,crasher,gonna,cant,ue,ons,orign,ned`

Reviewers: teemperor

Reviewed By: teemperor

Subscribers: teemperor, jholewinski, jvesely, nhaehnle, whisperity, jfb, cfe-commits

Differential Revision: https://reviews.llvm.org/D55475

llvm-svn: 348755
diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index 064de02..a8e3b85 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -167,7 +167,7 @@
 
   PreallocatedFunctionScope.reset(new FunctionScopeInfo(Diags));
 
-  // Initilization of data sharing attributes stack for OpenMP
+  // Initialization of data sharing attributes stack for OpenMP
   InitDataSharingAttributesStack();
 
   std::unique_ptr<sema::SemaPPCallbacks> Callbacks =