Remove SetForceInlineFlag from the js builtins. 

Bug: 
Change-Id: I962982509c82e4baba8dc32a0f163147c47daf34
Reviewed-on: https://chromium-review.googlesource.com/571803Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46756}