Bugfix: Disallow starting build-time check method names with 'test_'

[tldahlgren]

This PR flags attempts to run build-time check methods (https://spack.readthedocs.io/en/latest/packaging_guide.html#adding-installation-phase-tests) as stand-alone methods (https://spack.readthedocs.io/en/latest/packaging_guide.html#adding-stand-alone-tests) because the check method's name incorrectly starts with test_, which is now reserved for stand-alone test methods. Left alone, the test appears to pass when it was never actually run.

Motivation

Updates to stand-alone tests revealed a flaw in processing build-time check method names. If someone gives a build-time (e.g., @run_after) method a name starting test_, spack test run will claim it runs it successfully when it doesn't actually execute the method. This PR

For example, given a build-time check of test_execute for libstdcompat -- that calls make("test") -- basically runs as expected for spack install --test=root libstdcompat:

==> Testing package libstdcompat-0.0.20-h7drrbe
==> [2024-06-14-12:10:02.159556] Running build-time tests
==> [2024-06-14-12:10:02.159716] RUN-TESTS: build-time tests [check]
==> [2024-06-14-12:10:02.162396] 'make' '-j16' '-n' 'test'
==> [2024-06-14-12:10:02.183327] 'make' '-j16' 'test'
Running tests...
$spack/opt/spack/linux-rhel8-x86_64_v3/gcc-12.1.1/cmake-3.27.9-qg3djkkjmhzmgufb6de3qvpmyczz3fzf/bin/ctest --force-new-ctest-process 
Test project /tmp/dahlgren/spack-stage/spack-stage-libstdcompat-0.0.20-h7drrbezv6x7z5t354leunyyom4cafmc/spack-build-h7drrbe
    Start 1: stdcompat.integation1
1/1 Test #1: stdcompat.integation1 ............   Passed    0.00 sec

100% tests passed, 0 tests failed out of 1

Total Test time (real) =   0.00 sec
==> [2024-06-14-12:10:02.264505] 'make' '-j16' '-n' 'check'
==> [2024-06-14-12:10:02.284177] Target 'check' not found in Makefile

BUT it also appears to run successfully as a stand-alone test:

==> Testing package libstdcompat-0.0.20-h7drrbe
==> [2024-06-14-13:12:07.361367] test: test_execute: Test if libstdcompat executes correctly
PASSED: Libstdcompat::test_execute
==> [2024-06-14-13:12:07.364175] Completed testing
==> [2024-06-14-13:12:07.364308] 
===================== SUMMARY: libstdcompat-0.0.20-h7drrbe =====================
Libstdcompat::test_execute .. PASSED
============================= 1 passed of 1 parts ==============================

even though there is no way for the test to actually run/do anything.

TODO

• Add unit test(s)