go/token: replace map with array for looking up keywords

[soypat]

array access has considerable less overhead than map access
thus yielding benefits in performance and package initialization
cost.

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Patch Set 1:

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Patch Set 1:

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Patch Set 1:

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Patch Set 2: Commit-Queue+1

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Patch Set 2:

Dry run: CV is trying the patch.

Bot data: {"action":"start","triggered_at":"2025-11-29T23:06:25Z","revision":"6e27e7d0aa01c7ac0833fbb205c40367075e7eb4"}

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Patch Set 2: -Commit-Queue

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Patch Set 2:

This CL has passed the run

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Patch Set 2: LUCI-TryBot-Result+1

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Patch Set 2:

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Patch Set 2:

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This PR (HEAD: 0873615) has been imported to Gerrit for code review.

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Important tips:

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• To change your code in response to feedback:
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Message from Patricio Whittingslow:

Patch Set 2:

(1 comment)

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