Currently the first thing Make does it get the abi.Type of its argument,
and uses abi.TypeOf to do it. However, this has a problem for interface
types, since the type of the value stored in the interface value will
bleed through. This is a classic reflection mistake.

Fix this by implementing and using a generic TypeFor which matches
reflect.TypeFor. This gets the type of the type parameter, which is far
less ambiguous and error-prone.

Fixes #68990.

Change-Id: Idd8d9a1095ef017e9cd7c7779314f7d4034f01a7
Reviewed-on: https://go-review.googlesource.com/c/go/+/607355


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