ActivityManagerService: all users can handle freezer state in debug builds

Processes whose proxy maps exceed CRASH_AT_SIZE might need to disable
the freezer prior dumping their binding for debug purposes. This happens
on builds with the IS_DEBUGGABLE flag set, so ActivityManager needs to
allow freezer state toggling from any user in this case.

Bug: 178037173
Test: booted device with userdebug, forced interface dumps from all
binder proxies with no crashes.

Change-Id: Ib1f5c7f6ad2b404d56fef566b3d9f17730592762