swift234

Fix a nasty memory smasher in SILVTable that was causing one of my innocent (!)
tests to fail.  Basically, in the case of an empty vtable, SILVTable::create
was allocating space for 0 entries (sensible!) but then the default ctor fires
for the 1 element declared in the class, which would write off the end of the
memory block, leading to unpleasantness in random places later.


Swift SVN r11306