The benefit of this setting was largely lost due to wfDebug() having
been replaced with calls to Logger->debug() for much of our code.
This is motivated by making ResourcLoader debug=2 able to make
its concurrent load.php requests more quickly during local dev.
This effectively reverts T49960. I was wrong there, thinking that
this variable has no reason for being. The vast majority of the time,
these aren't of interest on subresource requests. It's trivial
to enable when wanted, and any non-debug level messages still come
through either way, including PHP runtime errors, exceptions,
warnings, etc.
This seems to make load.php about 50% faster for local development
when using mediawiki-docker.
I used `ab` to perform a load.php request 300 times. The mean was
320-360ms before this patch (with and without DebugRawPage=false),
and around 120-140ms with patch (with DebugRawPage=false, default).
Bug: T85805
Bug: T225730
Change-Id: I061419adebf43e83cd0103bdb9b7a3296a2a1122
1b218b2b54