tests: bsim: Bluetooth: Add -RealEncryption=1 to pass in-system UT

BSIM tests that enabled CONFIG_BT_CTLR_TEST=y now require
-RealEncryption to pass the Controller's in-system unit test
of ECB module.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>