[clang] [clangd] Avoid calling resolveTypeOfCallExpr() twice in HeuristicResolver::resolveExprToType() (PR #164353)

[kadir çetinkaya via cfe-commits]

kadircet wrote:

thanks a lot for the quick fix!

> @kadircet Do we have a good way of writing a regression test for something like this? Checking elapsed time seems flaky.

Unfortunately, no, I don't think we do :/ Best that comes to mind is have a callback somewhere down the stack when we resolve a dependent name, print the stack there and check for certain invariants (and hope that optimizations etc. don't trip that up). I don't think that's gonna be worthwhile either. 

Still having a unittest, with a comment saying "this shouldn't increase testing times", would likely be better than nothing. Long running tests are likely to catch some attention, at least from us :)

https://github.com/llvm/llvm-project/pull/164353