Treat phpdbg as run from the command line when checking PHP_SAPI

Treat phpdbg as run from the command line when checking PHP_SAPI

phpdbg is a gdb-style debugger for PHP that is run from the command
line. However, it has a different PHP_SAPI value, so it was impossible
to run maintenance scripts with it (until now).

To avoid having to check both PHP_SAPI values in a bunch of places,
introduce wfIsCLI() to easily check whether running from the
command-line or not.

We're (CI team) interested in generating code coverage with phpdbg
instead of xdebug, hence this patch.

Bug: T184043
Change-Id: Id1f994ca146d7858cd8bb6ab6cdbb7718ff524fb