Fix compiler error for type of NumAbbrevOps.

lib/Bitcode/NaCl/TestUtils/NaClBitcodeMungeWriter.cpp

 //===- NaClBitcodeMungeWriter.cpp - Write munged bitcode --------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // Implements method NaClMungedBitcode.write(), which writes out a munged
@@ skipping 491 matching lines @@
                      << "(" << static_cast<int64_t>(Value)
                      << ") in: " << Record << "\n";
   return false;
 }
 
 NaClBitCodeAbbrev *WriteState::buildAbbrev(
     const NaClBitcodeAbbrevRecord &Record) {
   // Note: Recover by removing abbreviation.
   NaClBitCodeAbbrev *Abbrev = new NaClBitCodeAbbrev();
   size_t Index = 0;
-  size_t NumAbbrevOps;
+  uint64_t NumAbbrevOps;
   if (!nextAbbrevValue(NumAbbrevOps, Record, Index))
     return deleteAbbrev(Abbrev);
   if (NumAbbrevOps == 0) {
     RecoverableError() << "Abbreviation must contain at least one operator: "
                        << Record << "\n";
     return deleteAbbrev(Abbrev);
   }
-  for (size_t Count = 0; Count < NumAbbrevOps; ++Count) {
+  for (uint64_t Count = 0; Count < NumAbbrevOps; ++Count) {
     uint64_t IsLiteral;
     if (!nextAbbrevValue(IsLiteral, Record, Index))
       return deleteAbbrev(Abbrev);
     switch (IsLiteral) {
     case 1: {
       uint64_t Value;
       if (!nextAbbrevValue(Value, Record, Index))
         return deleteAbbrev(Abbrev);
       if (!verifyAbbrevOp(NaClBitCodeAbbrevOp::Literal, Value, Record))
         return deleteAbbrev(Abbrev);
@@ skipping 73 matching lines @@
     NaClWriteHeader(Writer, true);
   }
   for (const NaClBitcodeAbbrevRecord &Record : *this) {
     if (!State.emitRecord(Writer, Record))
       break;
   }
   bool RecoverSilently =
       State.Results.NumErrors > 0 && !Flags.getTryToRecover();
   return State.finish(Writer, RecoverSilently);
 }