gollvm: minor unit test fixes

Fix a couple of small buglets in the unit test code.

Change-Id: Ibb9e83b12e6e227175069b284e2c4ab13b136b5d
Reviewed-on: https://go-review.googlesource.com/124376
Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/unittests/BackendCore/BackendVarTests.cpp b/unittests/BackendCore/BackendVarTests.cpp
index 60cebd1..237b1cf 100644
--- a/unittests/BackendCore/BackendVarTests.cpp
+++ b/unittests/BackendCore/BackendVarTests.cpp
@@ -725,7 +725,7 @@
   // Expect to see only one lifetime start, since A) loc1 is at the top
   // level, and B) loc2 uses loc1 as declVar.
   const char *expected = "@llvm.lifetime.start.p0i8(i64";
-  EXPECT_EQ(h.countInstancesInModuleDump(expected), 1);
+  EXPECT_EQ(h.countInstancesInModuleDump(expected), 1u);
 }
 
 }
diff --git a/unittests/DriverUtils/DriverUtilsTests.cpp b/unittests/DriverUtils/DriverUtilsTests.cpp
index f5bc815..643e8a8 100644
--- a/unittests/DriverUtils/DriverUtilsTests.cpp
+++ b/unittests/DriverUtils/DriverUtilsTests.cpp
@@ -264,7 +264,7 @@
       : triple_(trip),
         fs_(fileSystemContents),
         sysroot_(sysroot),
-        detector_(triple_, sysroot_, fs_)
+        detector_(triple_, "", sysroot_, fs_)
   {
     detector_.init();
   }