Check hidden API exemptions

Refuse to deal with newlines and null characters in
HiddenApiSettings.update(). Also disallow nulls in process start
arguments.

Bug: 316153291
Test: Treehugger for now
Change-Id: I83cd60e46407a4a082f9f3c80e937dbd522dbac4
(cherry picked from commit 7ba059e2cf0a2c20f9a849719cdc32b12c933a44)
1 file changed