Fix gn settings

R=machenbach@chromium.org

Change-Id: If25d0d34179b326f3a7b292f30299fe48a0aa1e2
Reviewed-on: https://chromium-review.googlesource.com/522127Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Jochen Eisinger <jochen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45684}

BUILD.gn

@@ -141,7 +141,7 @@ if (v8_enable_v8_checks == "") {
   v8_enable_v8_checks = is_debug
 }
 if (v8_check_microtasks_scopes_consistency == "") {
-  v8_check_microtasks_scopes_consistency = is_debug || v8_enable_v8_checks
+  v8_check_microtasks_scopes_consistency = is_debug || dcheck_always_on
 }
 
 # Specifies if the target build is a simulator build. Comparing target cpu