all: update vendored golang.org/x/tools

Update the vendored x/tools to pick up CL 380014, which updates the
ifaceassert vet analyzer to remove spurious errors for assertions
involving interfaces with type parameters.

This also picks up some superficial changes related to refactoring of
the x/tools/internal/typeparams API.

The following commands were used:

  go get -d golang.org/x/tools@master
  go mod tidy
  go mod vendor

Fixes #50658

Change-Id: I2f612fd186a1a260cab21860b192c9f6dc3f560f
Reviewed-on: https://go-review.googlesource.com/c/go/+/380777


Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Tim King <taking@google.com>