stick addressable constants into the constant pool

[Craig Powers]

Richard Henderson wrote:
>
> This did show up two testsuite bugs, which wrote to arguments that
> were given as constants.  Which now gives a SEGV, since Linux puts
> the constant pool in read-only memory.  I guess we'll have to see
> how much trouble this give us with dusty decks...

Based on my experience trying to track down a bug that occurred when
code I was working on accidentally redefined 0 via modifying a constant
argument (in DVF 5, I understand that later versions of CVF put
constants in read-only memory), I agree with Dale that a runtime failure
is an improvement.