Post-increment on globals mis-handled in LSL

[HaroldCindy]

We might not be doing the store correctly, post-increment doesn't update the lvalue correctly.

integer i;
default {
    state_entry() {
        while(i < 100) {
            ++i;
            print(i);
        }
    }
}

completes correctly, but changing it to a post-increment will print 0 forever.

[HaroldCindy]

e8603df