tests: use egrep with regular expression branches for compatibility
GNU grep allows you to use "a\|b" in a regular expression to match either
"a" or "b", but at least Solaris grep does not; only egrep allows for that.
And egrep considers "a+" to be "a{1,}" instead of an "a" and a literal plus
sign, so escape that as well.
(binary:application/octet-stream)