Fix typos in clang

Found via codespell -q 3 -I ../clang-whitelist.txt
Where whitelist consists of:

  archtype
  cas
  classs
  checkk
  compres
  definit
  frome
  iff
  inteval
  ith
  lod
  methode
  nd
  optin
  ot
  pres
  statics
  te
  thru

Patch by luzpaz! (This is a subset of D44188 that applies cleanly with a few
files that have dubious fixes reverted.)

Differential revision: https://reviews.llvm.org/D44188

llvm-svn: 329399
diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index 4e57e6c..926683d 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -66,7 +66,7 @@
 /// buildBlockDescriptor - Build the block descriptor meta-data for a block.
 /// buildBlockDescriptor is accessed from 5th field of the Block_literal
 /// meta-data and contains stationary information about the block literal.
-/// Its definition will have 4 (or optinally 6) words.
+/// Its definition will have 4 (or optionally 6) words.
 /// \code
 /// struct Block_descriptor {
 ///   unsigned long reserved;
@@ -330,7 +330,7 @@
     info.BlockSize = CharUnits::fromQuantity(Offset);
   } else {
     // The header is basically 'struct { void *; int; int; void *; void *; }'.
-    // Assert that that struct is packed.
+    // Assert that the struct is packed.
     assert(CGM.getIntSize() <= CGM.getPointerSize());
     assert(CGM.getIntAlign() <= CGM.getPointerAlign());
     assert((2 * CGM.getIntSize()).isMultipleOf(CGM.getPointerAlign()));
@@ -887,7 +887,7 @@
         const CGBlockInfo::Capture &enclosingCapture =
             BlockInfo->getCapture(variable);
 
-        // This is a [[type]]*, except that a byref entry wil just be an i8**.
+        // This is a [[type]]*, except that a byref entry will just be an i8**.
         src = Builder.CreateStructGEP(LoadBlockStruct(),
                                       enclosingCapture.getIndex(),
                                       enclosingCapture.getOffset(),