Add Go fuzz tests for OSS-Fuzz integration

[canolgun-commits]

Adds Go native fuzz targets covering critical code paths. Part of OSS-Fuzz integration proposal (google/oss-fuzz#15666). All targets verified: go test -fuzz=. -fuzztime=30s

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Patch Set 1:

(1 comment)

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Patch Set 1:

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[gopherbot]

Message from Ian Lance Taylor:

Patch Set 1:

(2 comments)

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