[clangd] Boost fuzzy match score by 2x (so a maximum of 2) when the query is...

[clangd] Boost fuzzy match score by 2x (so a maximum of 2) when the query is the full identifier name.

Summary: Fix a couple of bugs in tests an in Quality to keep tests passing.

Reviewers: ioeric

Subscribers: ilya-biryukov, MaskRay, jkorous, cfe-commits

Differential Revision: https://reviews.llvm.org/D47815

llvm-svn: 334089