There were a few issues in unary operators:
- Many were not compiling because the promote function had not
  been adjusted to take the new builtin functions into account
- abs and sign had not been implemented for int
- For the integer abs version, used pabsd. Removed the extra
  argument, which seemed unnecessary (abs should have 1 input,
  1 output, AFAIK).

Change-Id: If02c5040438e8c45c99fc7b3c55107448c85cf58
Reviewed-on: https://swiftshader-review.googlesource.com/4970Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>