Bug 690668 - TEST-UNEXPECTED-FAIL | c:\talos-slave\test\build\xpcshell\tests\toolkit\components\passwordmgr\test\unit\test_storage_legacy_2.js | test failed (with xpcshell return code: 0), see following log:. r=bsmedberg

xpcom/reflect/xptcall/src/md/win32/xptcstubs_x86_64.cpp

@@ -176,7 +176,9 @@ PrepareAndDispatch(nsXPTCStubBase* self, PRUint32 methodIndex, PRUint64* args,
 
         case nsXPTType::T_BOOL:
            if (iCount < PARAM_GPR_COUNT)
-              dp->val.b  = (bool)gprData[iCount++];
+              // We need cast to PRUint8 to remove garbage on upper 56-bit
+              // at first.
+              dp->val.b  = (bool)(PRUint8)gprData[iCount++];
            else
               dp->val.b  = *((bool*)ap++);
            break;