[test] Mark slow test

TBR=mslekova@chromium.org
NOTRY=true

Change-Id: I22af7e52ac457279b057e3e8c0b346e73e37ff86
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1598761Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61283}

test/mjsunit/mjsunit.status

@@ -167,6 +167,7 @@
   'es6/typedarray-construct-offset-not-smi': [PASS, SLOW],
   'harmony/futex': [PASS, SLOW],
   'harmony/regexp-property-script-extensions': [PASS, SLOW],
+  'ignition/regress-672027': [PASS, SLOW],
   'md5': [PASS, SLOW],
   'numops-fuzz-part*': [PASS, ['mode == debug', SLOW]],
   'readonly': [PASS, SLOW],