[heap] Disable concurrent marking on GYP builds.

Bug: chromium:694255
Change-Id: I58be876aa6db2e528f7d2e045e042657354575c7
Reviewed-on: https://chromium-review.googlesource.com/637393Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47637}

gypfiles/features.gypi

@@ -82,13 +82,7 @@
     'v8_check_microtasks_scopes_consistency%': 'false',
 
     # Enable concurrent marking.
-    'conditions': [
-      ['v8_target_arch=="x64" or v8_target_arch=="ia32"', {
-        'v8_enable_concurrent_marking%': 1,
-      },{
-        'v8_enable_concurrent_marking%': 0,
-      }]
-    ],
+    'v8_enable_concurrent_marking%': 0,
   },
   'target_defaults': {
     'conditions': [