Disable app shim signature check

App shims aren't starting on 73.0.3677.0.

TBR=sdy

Bug: 624228
Change-Id: Ied8fdac4986b61db99333527b118f319d808d5c7
Reviewed-on: https://chromium-review.googlesource.com/c/1424159
Commit-Queue: ccameron <ccameron@chromium.org>
Reviewed-by: ccameron <ccameron@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624478}
1 file changed