Adding CHECKED_OUT_VERSION to .gitignore.
Adding CHECKED_OUT_VERSION to .gitignore.

Adding CHECKED_OUT_VERSION in test/simdjs so that
the bots don't revert and redownload each time.

LOG=N
BUG=None
TEST=None
R=littledan@chromium.org,machenbach@chromium.org

Review URL: https://codereview.chromium.org/1242863003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#29826}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh