[clang-tools-extra] [clangd] Add a unit test suite for HeuristicResolver (PR #121313)

[Nathan Ridge via cfe-commits]

HighCommander4 wrote:

In the latest update, I use the new `hasDependentName()` matcher added in https://github.com/llvm/llvm-project/issues/121610 to make the matchers using `dependentScopeDeclRefExpr()` more specific.

https://github.com/llvm/llvm-project/pull/121313