Currently the handle test code has a lot of duplicate type parameters
that are already inferred. This results in IDE warnings which are
annoying. Clean this up by consistently explicitly calling out the type
in the argument, not the type parameter.

Change-Id: I756203f37fc97c793cd5c5e612c6fd1802a84bc1
Reviewed-on: https://go-review.googlesource.com/c/go/+/607356


Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>