cmd/go: respect -n flag in 'go tool' command

[KirtanSoni]

In 'go tool -n' command, '-n' flag wasn't being properly respected, causing the command to rebuild the package & store the cache every time. fix ensures that 'go tool -n' consistent with the documentation.

Fixes #72824

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Patch Set 1:

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Message from Kirtan Soni:

Patch Set 3:

(2 comments)

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Patch Set 3:

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Patch Set 3:

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Patch Set 3: Code-Review+1

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Patch Set 3:

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This PR (HEAD: cb5699f) has been imported to Gerrit for code review.

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