[clangd] Handle PresumedLocations in IncludeCollector

Summary:
This will enable extraction of correct line locations in preamble patch
for includes.

Reviewers: sammccall

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D78740