Splits without restart

In specific cases [as determined by the installer], we can install
splits without restarting the application. The split must be purely
additive [i.e. it should not modify class(es)/resource(s) defined
in the base or other splits. Otherwise, the behaviour could be
inconsistent [e.g. if a modified class was already loaded, the
modified version won't be loaded until the process is restarted].
The platform does not perform any verification that the split is
purely additive.

Bug: 26463098
Change-Id: I3526c3b1b847a8e0afabc7a4787fa770422196b7