revlog-compression: use zstd by default (if available)
As see in changeset
bb271ec2fbfb, zstd is 20% to 50% faster for reading and
writing.
Use take advantage of the new config behavior to try zstd by default, falling
back to zlib is zstd is not available on that plateform.
Differential Revision: https://phab.mercurial-scm.org/D10326
#require test-repo execbit
$ . "$TESTDIR/helpers-testrepo.sh"
$ cd "`dirname "$TESTDIR"`"
look for python scripts without the execute bit
$ testrepohg files 'set:**.py and not exec() and grep(r"^#!.*?python")'
[1]
look for python scripts with execute bit but not shebang
$ testrepohg files 'set:**.py and exec() and not grep(r"^#!.*?python")'
[1]
look for shell scripts with execute bit but not shebang
$ testrepohg files 'set:**.sh and exec() and not grep(r"^#!.*(ba)?sh")'
[1]
look for non scripts with no shebang
$ testrepohg files 'set:exec() and not **.sh and not **.py and not grep(r"^#!")'
[1]