Add command to allow setting of some permission flags from shell

Add the "pm set/clear-permission-flags" adb commands, which will allow a
developer to set the USER_SET, USER_FIXED, REVIEW_REQUIRED,
REVOKED_COMPAT, and REVOKE_WHEN_REQUESTED flags via adb.

Test: manual
Fixes: 229321394
Change-Id: I6a85466ce25ce24eececde936214cfc033fafac0