[query] Fix loop memory management

[johnc1231]

Recur needs to emit its args into region 1, then copy them into region 2. Also the emitI result needs to emit into loopRef.r1 before being copied into the main region.

[johnc1231]

Trying to cook up a python test that wouldn't pass without this, surprisingly annoying.

[tpoterba]

I think:

return hl.experimental.loop(
    lambda f, array, idx: hl.if_else(idx > 10,  array, f(array.extend(hl.str(idx)), idx + 1),
    hl.tarray(hl.tstr), ['foo'], 1)

[tpoterba]

Could also do a scala test that asserts about memory usage.

[johnc1231]

Added the python test, it returns bogus results in main so it's a good one.