net/mail: ParseAddress: quadratic complexity in consumeComment [1.26 backport]

[gopherbot]

@neild requested issue #78566 to be considered for backport to the next 1.26 minor release.

@gopherbot please open backport issues for this security fix.

[gopherbot]

Change https://go.dev/cl/763800 mentions this issue: [release-branch.go1.26] net/mail: fix quadratic complexity in consumeComment