Install notion of diagnostic handler into PNaCl bitcode readers.

lib/Bitcode/NaCl/TestUtils/NaClBitcodeMunge.cpp

Index: lib/Bitcode/NaCl/TestUtils/NaClBitcodeMunge.cpp
diff --git a/lib/Bitcode/NaCl/TestUtils/NaClBitcodeMunge.cpp b/lib/Bitcode/NaCl/TestUtils/NaClBitcodeMunge.cpp
index 0d5e70c583062ed841a96be3ace1efb7c4cd4539..ff347f7eefa47db723f879b1ff5fb3b7085fbe65 100644
--- a/lib/Bitcode/NaCl/TestUtils/NaClBitcodeMunge.cpp
+++ b/lib/Bitcode/NaCl/TestUtils/NaClBitcodeMunge.cpp
@@ -141,11 +141,9 @@ bool NaClParseBitcodeMunger::runTest(const uint64_t Munges[], size_t MungesSize,
     return cleanupTest();
 
   LLVMContext &Context = getGlobalContext();
-
-  raw_ostream *VerboseStrm = VerboseErrors ? &getDumpStream() : nullptr;
   ErrorOr<Module *> ModuleOrError =
       NaClParseBitcodeFile(MungedInput->getMemBufferRef(), Context,
-                           VerboseStrm);
+                           redirectNaClDiagnosticToStream(getDumpStream()));
   if (ModuleOrError) {
     if (VerboseErrors)
       getDumpStream() << "Successful parse!\n";