build/rust/win: Tweak how we ask rustc to link to the CRT

We currently jump through some hoops because rustc doesn't have
a built-in way to link to the debug versions of the CRT.

This makes the following changes:
* When linking to the non-debug version, always use
  -Ctarget-feature=[+-]crt-static
* When linking to the debug version, also pass
  -Clink-arg=/nodefaultlib:libcmt.lib,
  -Clink-arg=/nodefaultlib:msvcrt.lib. A new version of
  rustc will implicitly add these release versions of the
  C runtime, and since we don't use the crt-static feature
  toggle when linking the debug versions, it'll even link
  the wrong one (msvcrt when we link in libcmtd), causing
  problems. Passing these to our current rustc should be safe.
  See bug for details.

Bug: 336318586
Change-Id: I7d04e97e8a0bb41abc942de93f5cb1afe67090d8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5476668
Auto-Submit: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Hans Wennborg <hans@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1291322}