Allow more slop in TypefaceMacVariation test

CoreText in macOS 14 and later appears to be rounding the axis values
(especially `opsz`) in a new and interesting way. Most issues are with
CoreText rounding down oddly (single ULP differences) but `opsz` appears
to be rounded quite a bit. Allow for CoreText to do more rounding but
still make sure the values are still about right while investigating.

Change-Id: I95f5c276b170d2516e68407c8473d518a32644b3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/937038
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
2 files changed