[analyzer] Add -ftime-trace scopes for region-store bindings and removeDead (#125884)
From investigation of a few slow analysis cases, I discovered that
`RegionStoreManager::bind*` and `ExprEngine::removeDead` are often the
slowest actions. This change adds explicit scope to the time trace
generated by `-ftime-trace` to enable easy diagnostics of the cases when
these functions are the slowdown culprits.
--
CPP-6109