This commit extends developers ability to use jump-to-def in C/C++ files opened in the VSCode extension.
Before, jump-to-def starting with code in a template instantiation did not work.
Furthermore, this fixes a bug, as the list of all references of a location did not include template instantiations.
This gains some performance by not computing locations for all
expressions since we are only interested in calls and variable accesses.
The `Top::hasLocationInfo` predicate goes from 2m28s to 1m32s on
Chromium.
This predicate was slow, mostly because it's just very large. A manual
join order cuts the run time on Chromium from
definitions::Top::hasLocationInfo_dispred#ffffff ..................... 3m23s
definitions::MacroAccessWithHasLocationInfo::hasLocationInfo#ffffff .. 1m56s
to
definitions::Top::hasLocationInfo#ffffff .... 2m28s
The main slowdown was the two uses of `SCAN` to reorder columns in the
RA.
We currently erroneously keep mentions of class instantiations, which
can lead to bad performance on template-heavy code bases. We never
want to link those anyway, so we can simply suppress them.
