Bluetooth: pause/resume advertising around suspend

Currently, the controller will continue advertising when the system
enters suspend. This patch makes sure that all advertising instances are
paused when entering suspend, and resumed when suspend exits.

The Advertising and Suspend/Resume test suites were both run on this
change on 4.19 kernel with both hardware offloaded multi-advertising and
software rotated multi-advertising. In addition, a new test was added
that performs the following steps:
* Register 3 advertisements via bluez RegisterAdvertisement
* Verify reception of all advertisements by remote peer
* Enter suspend on DUT
* Verify failure to receive all advertisements by remote peer
* Exit suspend on DUT
* Verify reception of all advertisements by remote peer

Signed-off-by: Daniel Winkler <danielwinkler@google.com>
Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>