Adjust the has_errors* methods.

Currently `has_errors` excludes lint errors. This commit changes it to
include lint errors.

The motivation for this is that for most places it doesn't matter
whether lint errors are included or not. But there are multiple places
where they must be includes, and only one place where they must not be
included. So it makes sense for `has_errors` to do the thing that fits
the most situations, and the new `has_errors_excluding_lint_errors`
method in the one exceptional place.

The same change is made for `err_count`. Annoyingly, this requires the
introduction of `err_count_excluding_lint_errs` for one place, to
preserve existing error printing behaviour. But I still think the change
is worthwhile overall.

compiler/rustc_interface/src/passes.rs

@@ -772,7 +772,7 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) -> Result<()> {
     // lot of annoying errors in the ui tests (basically,
     // lint warnings and so on -- kindck used to do this abort, but
     // kindck is gone now). -nmatsakis
-    if let Some(reported) = sess.dcx().has_errors() {
+    if let Some(reported) = sess.dcx().has_errors_excluding_lint_errors() {
         return Err(reported);
     } else if sess.dcx().stashed_err_count() > 0 {
         // Without this case we sometimes get delayed bug ICEs and I don't