tests: use grep -F instead of obsolescent fgrep
Testing on Fedora 38 failed with:
fgrep: warning: fgrep is obsolescent; using grep -F
The warning comes from
https://git.savannah.gnu.org/cgit/grep.git/commit/?id=
a9515624709865d480e3142fd959bccd1c9372d1
. For further anecdotal evidence of the change, see
https://www.phoronix.com/news/GNU-Grep-3.8-Stop-egrep-fgrep .
grep -F is POSIX, but there is a risk that it doesn't work the same on all
platforms - especially older Unix versions. It should however always be
possible to put a GNU grep in $PATH before running the tests.
{
// Enforcing
"eqeqeq" : true, // true: Require triple equals (===) for comparison
"forin" : true, // true: Require filtering for..in loops with obj.hasOwnProperty()
"freeze" : true, // true: prohibits overwriting prototypes of native objects such as Array, Date etc.
"nonbsp" : true, // true: Prohibit "non-breaking whitespace" characters.
"undef" : true, // true: Require all non-global variables to be declared (prevents global leaks)
// Environments
"browser" : true // Web Browser (window, document, etc)
}