Add an option to abort when a panic alert occurs

Prompted by https://dolphin.ci/#/builders/24/builds/985

A 1-character typo in a recent PR caused FifoCI builds to break
horribly and spew millions of panic alerts until buildbot crashed.

This PR adds a new config option -- defaulting to off -- that allows
Dolphin to abort early on when a panic alert occurs instead of
continuing forever.

Source/Core/Common/MsgHandler.h

@@ -49,6 +49,7 @@ bool MsgAlertFmt(bool yes_no, MsgType style, const S& format, const Args&... arg
 }
 
 void SetEnableAlert(bool enable);
+void SetAbortOnPanicAlert(bool should_abort);
 
 // Like fmt::format, except the string becomes translatable
 template <typename... Args>