Drop jumbo support for .S asm files

We don't need it and it doesn't work. It's probably been ok up
until now because we have never had more than one S file per
build target.

See errors at
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Jumbo%20Win%20x64/22538

R=fs@opera.com

Change-Id: Idde99aba83e01c0111e5a50590e319993e0effaa
Reviewed-on: https://chromium-review.googlesource.com/c/1340312
Commit-Queue: Daniel Bratell <bratell@opera.com>
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#608826}
2 files changed