strconv: use generics to reduce redundant helper functions
Benchstat shows there are no noticeable performance changes here.
Change-Id: If2250334fe6664986f044cbaabfa1bfc84f871f7
GitHub-Last-Rev:
d41a498d54483759b9c85c3d8efa848c0cc1bbd9
GitHub-Pull-Request: golang/go#66266
Reviewed-on: https://go-review.googlesource.com/c/go/+/570935
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Commit-Queue: Ian Lance Taylor <iant@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>