Remote: handle early return of compressed blobs uploads

This is an implementation of this REAPI spec update:
https://github.com/bazelbuild/remote-apis/pull/213

Here's a bazel-remote build that can be used to test this change:
https://github.com/buchgr/bazel-remote/pull/527

Fixes #14654

Closes #14870.

PiperOrigin-RevId: 430167812
diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index a95cecd..6936c81 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -20,6 +20,7 @@
 Kevin Bierhoff <kmb@google.com>
 Klaas Boesche <klaasb@google.com>
 Phil Bordelon <sunfall@google.com>
+Mostyn Bramley-Moore <mostyn@antipode.se>
 Jon Brandvein <brandjon@google.com>
 Volker Braun <vbraun.name@gmail.com>
 Thomas Broyer <t.broyer@ltgt.net>