I accidentally did a signed comparison of the size_t values passed in
for three of the _chk functions. Changing them to unsigned compares.
Add three new tests to verify this failure is fixed.
Bug: 10691831
Merge from internal master.
(cherry-picked from 883ef2499c2ff76605f73b1240f719ca6282e554)
Change-Id: Id9a96b549435f5d9b61dc132cf1082e0e30889f5