dev-embedded/simulavr: drop dead SRC_URI, fetch via git-r3 only
The ebuild inherits git-r3, which unconditionally exports
src_unpack and clones EGIT_COMMIT="release-${PV}" via git. The
SRC_URI tarball from a cgit snapshot endpoint was never actually
used for unpacking, but portage's fetch phase still tried (and
hung/failed) to download it before src_unpack ran, breaking emerge
even though the git tag itself resolves fine.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>