FreeBSD_HEAD_arm64 - Build #1095 - Fixed

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FreeBSD_HEAD_arm64 - Build #1095 - Fixed:

Build information: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_arm64/1095/
Full change log: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_arm64/1095/changes
Full build log: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_arm64/1095/console

Change summaries:

287602 by jhb:
Use _exit() instead of exit() in child processes created during tests.

Suggested by:	kib

287601 by jhb:
Add a test to verify that a traced process sees its original parent via
getppid() after a debugger process that is not the parent has attached.

Reviewed by:	kib (earlier version)
Differential Revision:	https://reviews.freebsd.org/D3615