[dev.typeparams] go/types: fix the type parameter index in applyTypeFunc
We should preserve type parameter indices when transforming them using
applyTypeFunc.
Change-Id: Ib75f5cf1a146bd7e6850368fa954c1affcba3ad1
Reviewed-on: https://go-review.googlesource.com/c/go/+/327269
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com> Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>