allow passing in AITER_CORE_DIR as env var

[842974287]

Due to python package packing, we need to specify a different dir as the core dir in our prod env.

[valarLip]

looks like you can reuse this one

aiter/aiter/jit/core.py

Line 106 in ee66417

def get_user_jit_dir():

[842974287]

@valarLip Do you mean switch to use get_user_jit_dir() in utils.py? It feels like the result from get_user_jit_dir() and AITER_CORE_DIR serves different purpose though. Like AITER_CORE_DIR is more for a place to look up aiter code/resource files while get_user_jit_dir() is a dir to use for JIT compilation.

[valarLip]

could you please describ more about your use case? i don't get the point why we need specify the rscr dir