hash/maphash: parallel run test
This reduces the go test hash/maphash time
by more than half.
Change-Id: If184ca99544809c86b4c1baeb45d3afede91b41a
GitHub-Last-Rev:
440c35f8b544a16cc733e3291f963f738dd59a47
GitHub-Pull-Request: golang/go#65739
Reviewed-on: https://go-review.googlesource.com/c/go/+/564576
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>