bpo-38122: minor fixes to AsyncMock spec handling (GH-16099)
bpo-38122: minor fixes to AsyncMock spec handling (GH-16099)

Backports: 14fd925a18fe3db0922a7d798e373102fe7a8a9c
Signed-off-by: Chris Withers <711c73f64afdce07b7e38039a96d2224209e9a6c@withers.org>

testing-cabal/mock