[turbofan] Blacklist test case which needs investigation.

TBR=jarin@chromium.org

Review URL: https://codereview.chromium.org/1557833002 .

Cr-Commit-Position: refs/heads/master@{#33077}

test/mjsunit/mjsunit.status

@@ -168,6 +168,7 @@
 
   # Assumptions about optimization need investigation in TurboFan.
   'regress-sync-optimized-lists': [PASS, NO_VARIANTS],
+  'regress/regress-store-uncacheable': [PASS, NO_VARIANTS],
 
   # issue 4078:
   'allocation-site-info': [PASS, NO_VARIANTS],