Trim quotes from prefix: search

All of the rest of our syntax supports quotes so prefix: may as well too.

This also addes some tests that check for
I7e602d005a8b2786942b76b7185882e5107942c4 from core.  We can ignore them
until that behavior is merged there.

Bug: 60489
Change-Id: I6e1c9c0a3234f1aa55cba37867a401204f0a1a8c
Merge "Trim quotes from prefix: search"