I find it convenient to have access to JS_ReadObject and JS_WriteObject
from JS land. That's precisely the functionality that tests/bjson.c
provides, ergo, move it into quickjs-libc.c
Change JS_WriteObject() and JS_WriteObject2() to write little-endian
data and update JS_ReadObject() to byte-swap data when running on a
big-endian system.
Obsoletes the JS_WRITE_OBJ_BSWAP flag, it is now a no-op.
Fixes: https://github.com/quickjs-ng/quickjs/issues/125