Workaround for gtest-related breakage: https://github.com/facebook/hermes/issues/388

--- external/llvh/CMakeLists.txt.orig	2020-12-17 03:26:48 UTC
+++ external/llvh/CMakeLists.txt
@@ -27,4 +27,4 @@ add_subdirectory(lib)
 add_subdirectory(utils/FileCheck)
 add_subdirectory(utils/not)
 add_subdirectory(utils/count)
-add_subdirectory(utils/unittest)
+#add_subdirectory(utils/unittest)