Fix _ExtInt(1) to be a i1 in memory.

The _ExtInt(1) in getTypeForMem was hitting the bool logic for expanding
to an 8 bit value.  The result was an assert, or store i1 %0, i8* %2, align 1
since the parameter IS an i1.  This patch changes the 'forMem' test to
exclude ext-int from the bool test.