tests/test-hghave

tests: add glob matching for unified tests

This adds a " (glob)" marker that works like a simpler version of
(re): "*" is converted to ".*", and "?" is converted to ".".

Both special characters can be escaped using "\", and the backslash
itself can be escaped as well.

Other glob-style syntax, like "**", "[chars]", or "[!chars]", isn't
supported.

#!/bin/sh
# Testing that hghave does not crash when checking features

"$TESTDIR/hghave" --test-features 2>/dev/null