Fix signed/unsigned comparison warning and print format

The print format was causing at least 2 unit-test failures from r331971.

The signed/unsigned comparison warnings only appeared to affect two lines but
it was unclear whether it might just pop up on other lines, so I have been
explicit in all the literals in the tests.

There were other bot unit-test failures that I am still investigating.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331978 91177308-0d34-0410-b5e6-96231b3b80d8