cmd/go: support overlaying go.mod files

This change updates the lockedfile package to open files using the
new fsys.OpenFile function. The logic of fsys.Open has been moved into
fsys.OpenFile, and fsys.Open is now just a light wrapper around it.

For #39958

Change-Id: I552f1a45ac00ac06b5812008d17a61e610b4b113
Trust: Michael Matloob <>
Run-TryBot: Michael Matloob <>
TryBot-Result: Go Bot <>
Reviewed-by: Jay Conrod <>
Reviewed-by: Bryan C. Mills <>
8 files changed
tree: 60992647429c76300b91d7c9c0eb99b77ae76761
  1. .gitattributes
  2. .github/
  3. .gitignore
  11. api/
  12. doc/
  13. favicon.ico
  14. lib/
  15. misc/
  16. robots.txt
  17. src/
  18. test/

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