Remove IS_MINIMAL_TOOLCHAIN

This was only set in (some) nacl builds, it's always false now.

Bug: 423859723
Change-Id: Ic7e13a939f23c6f50c1ce27221056aeb325538c7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6678414
Auto-Submit: Nico Weber <thakis@chromium.org>
Commit-Queue: Derek Schuff <dschuff@chromium.org>
Reviewed-by: Derek Schuff <dschuff@chromium.org>
Owners-Override: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1479393}
NOKEYCHECK=True
GitOrigin-RevId: 755e965d7c5fab4767934c37bcd524b0cc07adc1