Saves about 500 bytes on unix x64 and enables CPython-conform
usage of passing a re object to these functions.

For ports that have a system malloc which is not garbage collected (eg
unix, esp32), the stream object for the DB must be retained separately to
prevent it from being reclaimed by the MicroPython GC (because the
berkeley-db library uses malloc to allocate the DB structure which stores
the only reference to the stream).

Although in some cases the user code will explicitly retain a reference to
the underlying stream because it needs to call close() on it, this is not
always the case, eg in cases where the DB is intended to live forever.

Fixes issue #5940.

So this setting could be used by other source files if needed.

This is run with uncrustify 0.70.1, and black 19.10b0.