inthandler: process multiple interrupts per exception.
inthandler: process multiple interrupts per exception.

Currently the exception handler only processes the first interrupt
it sees, and then exits. If there were other interrupts pending,
the exception will trigger again to process them. This is a bit of
a useless overhead for the currently rare case of two interrupts happen
almost at the same time.

It is more efficient to check all kind of pending interrupts, and
process them all instead in a single exception.

DragonMinded/libdragon,DragonMinded/libdragon,DragonMinded/libdragon