[wasm] Un-skip previously flaky tests

BUG= v8:6132
NOTRY=true

Change-Id: I47beef4f90b37c259252b86a856f5bc075979084
Reviewed-on: https://chromium-review.googlesource.com/461299
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44172}

test/mjsunit/mjsunit.status

@@ -723,10 +723,6 @@
   'math-*': [SKIP],
   'unicode-test': [SKIP],
   'whitespaces': [SKIP],
-
-  # BUG(v8:6132).
-  'wasm/grow-memory': [PASS, ['gc_stress', SKIP]],
-  'wasm/import-memory': [PASS, ['gc_stress', SKIP]],
 }],  # variant == wasm_traps
 
 ]