Tests: Bluetooth: Classic: Bumble `power_on()` will fail on Linux

On Linux, the function `power_on()` of Bumble will fail when executing
even-numbered test cases.

From the `btmon` log, the controller will not reply the `HCI Command:
Reset` when the issue occurs.

Add a try-except to catch the exception of the function `power_on()`,
and retry to call the function `power_on()` until issue no longer
occurs. Or, the test will fail due to the timeout.

Signed-off-by: Lyle Zhu <lyle.zhu@nxp.com>