bootstrap: keep intrinsic-test path compatibility

[HNO3Miracle]

Fixes a failure in the ISCAS/Ruyi RISC-V CI:

https://community-ci.openruyi.cn/ruyici/job/RustCI/job/Rustci-daily-job/

The CI currently invokes:

x.py test --stage 2 library/stdarch/crates/intrinsic-test

Since IntrinsicTest::should_run was changed to register only the
intrinsic-test alias, this invocation fails during bootstrap path resolution
with:

ERROR: no `test` rules matched ["library/stdarch/crates/intrinsic-test"]

The failure is visible in the CI artifact for run 38021940247:

https://community-ci.openruyi.cn/misc/rustci/gate-ci/2026-10-10/baff6033863e38fe5f57242ea99b7f960ce9863c/failure-case.log

This PR restores the historical path as an additional selector. The existing
architecture check still skips intrinsic-test on unsupported hosts such as
RISC-V.

However, I understand that registering the path also makes x test library
select this step. If that behavior is intentionally forbidden, the better fix
is to update the external CI invocation to use intrinsic-test instead, and
this PR should be closed rather than changing bootstrap path matching.

Tests:

• ./x.py test bootstrap

r? @Kobzol

[rustbot]

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[Kobzol]

Hi, what exactly do you mean by "external CI jobs"? We specifically made this change because we don't want x test library to run the intrinsic tests.

[HNO3Miracle]

Thanks for pointing this out.

By “external CI jobs”, I mean the ISCAS/Ruyi RISC-V CI:

https://community-ci.openruyi.cn/ruyici/job/RustCI/job/Rustci-daily-job/

That CI currently invokes:

./x.py test --stage 2 library/stdarch/crates/intrinsic-test

After #159898, this fails during bootstrap path resolution because the step only registers the intrinsic-test alias.

The failure is visible here:

https://community-ci.openruyi.cn/misc/rustci/gate-ci/2026-10-10/baff6033863e38fe5f57242ea99b7f960ce9863c/failure-case.log

I agree that registering the path makes x test library select the intrinsic tests, which is undesirable if that behavior is intentional. In that case, the correct fix is to update the external CI to invoke intrinsic-test instead, and this PR should be closed rather than changing bootstrap path matching.

I will follow your preference here.