Main Conformance: Re-adjust TANH compliance check

Add lower bound to ABS ERROR checks to allow for cancellation of
small values in error bounds checking.
Re-adjust the error bounds multiplier to match the specification.
Fix up naming of verify library info structs.

Signed-off-by: Jeremy Johnson <jeremy.johnson@arm.com>
Change-Id: I3e178c3d7d59fef9c3696178646b23ed2a3ffc61