FreeBSD-main-amd64-test - Build #21864 - Still Unstable

FreeBSD-main-amd64-test - Build #21864 (c9e4d25052065d1e0cbdb3a0eea3f21c9225d1d1) - Still Unstable

Build information: https://ci.FreeBSD.org/job/FreeBSD-main-amd64-test/21864/
Full change log: https://ci.FreeBSD.org/job/FreeBSD-main-amd64-test/21864/changes
Full build log: https://ci.FreeBSD.org/job/FreeBSD-main-amd64-test/21864/console

Status explanation:
"Unstable" - some tests are suspected being broken by the following changes
"Still Unstable" - the failing test cases have not been fixed by these
                   following changes and this is a notification to note that
                   these changes have not been fully tested by the CI system

Change summaries:
(Those commits are likely but not certainly responsible)

c9e4d25052065d1e0cbdb3a0eea3f21c9225d1d1 by kib:
iommu_gas: add iommu_gas_remove()



The failed test cases:

2 tests failed.
FAILED:  usr.bin.tail.tail_test.follow_stdin

Error Message:
atf-check failed; see the output of the test for details

FAILED:  lib.libc.locale.c16rtomb_test.c16rtomb_utf_8_test

Error Message:
/usr/src/lib/libc/tests/locale/c16rtomb_test.c:145: c16rtomb(buf, L'A', &s) == (size_t)-1 not met