JIT: fix loop alignment issue (#70936)

JIT: fix loop alignment issue (#70936)

When scanning to figure out which blocks should have alignment padding, we can
sometimes encounter a block in a loop before we see the block at the top of the
loop.. If so, remove alignment for that loop, otherwise the emitter code
handling alignment gets tripped up. Even if the emitter could handle this case,
it would be padding with the loop, not before it.

The problematic block reordering is done much earlier. At some point we need to
revisit this as it is making nonsensical ordering decisions. But we'll tolerate
it for now.

Fixes #70152.