Run the nightly CI job when pulley files are touched in a PR

After bytecodealliance#9251, we will check that
Pulley builds with rustc's experimental tail calls feature enabled in the
nightly CI job. So if we touch any pulley source files in a PR, we should also
run that job in the PR's CI.

.github/workflows/main.yml

@@ -246,6 +246,9 @@ jobs:
           if grep -q debug names.log; then
             echo run-dwarf=true >> $GITHUB_OUTPUT
           fi
+          if grep -q pulley commits.log; then
+            echo test-nightly=true >> $GITHUB_OUTPUT
+          fi
         fi
         matrix="$(node ./ci/build-test-matrix.js ./commits.log ./names.log $run_full)"
         echo "test-matrix={\"include\":$(echo $matrix)}" >> $GITHUB_OUTPUT