Save invocation info of dex2oat runs.

It is useful to have the exact dex2oat invocation used to generate
artifacts for some tests. This adds the --write-invocation-to= flag to
the build to save this information.

Test: m droid
Bug: 119332327
Change-Id: Ie17ac73c790b0c55ef5569f03d11e7f03b5ef035