tests/helper-runtests.sh

fsmonitor: properly handle str ex.msg

ex.msg is always a str, since pywatchman uses str for exception messages.

This commit removes a b'' from a string compare to avoid types
mismatch and adds a coercion to bytes before stuffing the exception
message on our local exception type, which uses bytes for the message
elsewhere in this file.

Differential Revision: https://phab.mercurial-scm.org/D7855

#
# Avoid interference from actual test env:

unset HGTEST_JOBS
unset HGTEST_TIMEOUT
unset HGTEST_PORT
unset HGTEST_SHELL