Fail toolstate like before on the PR builder

The previous commit changed toolstate to never fail the build (excluding
beta week and beta/stable branches). This amends that logic to also fail
the PR builder "as if" we were on beta, since a PR author changing a
submodule likely does want some indication of failure rather than silent
acceptance. Ideally, there'd be some way to provide a "warning" but I
don't believe that's possible with current set of checks.

Author: Mark-Simulacrum

src/ci/azure-pipelines/pr.yml

@@ -32,4 +32,5 @@ jobs:
       parameters:
         only_on_updated_submodules: 'yes'
   variables:
+    FORCE_FAIL_TOOLSTATE: true
     IMAGE: x86_64-gnu-tools

src/ci/docker/x86_64-gnu-tools/checktools.sh

@@ -61,6 +61,11 @@ verify_submodule_changed() {
             if [ $SIX_WEEK_CYCLE -ge 35 ]; then
                 exit 3
             fi
+            # we want the PR builder to error out even though the auto branch
+            # builder will not
+            if [ -n "$FORCE_FAIL_TOOLSTATE" ]; then
+                exit 3
+            fi
         fi
     fi
 }