[clangd] Fix crash in tests in debug mode.
[clangd] Fix crash in tests in debug mode.

Caused by the lack of checking of an Expected value in the previous
commit.

git-svn-id: a34e9779ed74578ad5922b3306b3d80a0c825546@324736 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/clang-tools-extra,llvm-mirror/clang-tools-extra,llvm-mirror/clang-tools-extra,llvm-mirror/clang-tools-extra