dashboard: make darwin-amd64-aws race builder actually run race
dashboard: make darwin-amd64-aws race builder actually run race

race builders must have a name ending in -race. Switch the name to match
that rule.

For golang/go#48945.

Change-Id: I69caf2e4d2e059a666d14dfe325a275e467488de
Reviewed-on: https://go-review.googlesource.com/c/build/+/432859
Run-TryBot: Michael Pratt <e7f1edc6d5aa9f6c8c377425db8f1a5816cbbb88@google.com>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Cherry Mui <d62e63aa42ce272d7b6a5055d97e942b33a34679@google.com>

golang/build,golang/build,golang/build,golang/build