Removed all references to builds [v8_mips_compile_rel,
V8 Mips - builder, V8 Mips - big endian - nosnap] from
configuration files in master branch. Also removed
dead code and unused artifacts that resulted from the
above mentioned changes.

Bug: v8:8858
Change-Id: If9f8d9db433a50997f35219ef4ea9d8a91a1a495
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1798431Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Tamer Tas <tmrts@chromium.org>
Commit-Queue: Liviu Rau <liviurau@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63785}