Use less sync IPC for ITP testRunner methods.
Created attachment 393760 [details] Patch
Created attachment 393761 [details] Patch
Created attachment 393765 [details] Patch
Comment on attachment 393765 [details] Patch r=me, watch out for flakiness caused by this.
Comment on attachment 393765 [details] Patch Clearing flags on attachment: 393765 Committed r258566: <https://trac.webkit.org/changeset/258566>
All reviewed patches have been landed. Closing bug.
<rdar://problem/60547182>