Revert "math: add Compare and Compare32"

Revert "math: add Compare and Compare32"

This reverts CL 459435.

Reason for revert: Tests failing on MIPS.

Change-Id: I9017bf718ba938df6d6766041555034d55d90b8a
Reviewed-on: https://go-review.googlesource.com/c/go/+/467255
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Akhil Indurti <aindurti@gmail.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>