build: build failure on x_tools-go1.22-linux-riscv64

[gopherbot]

#!watchflakes
default <- builder == "x_tools-go1.22-linux-riscv64" && repo == "tools" && mode == "build"

Issue created automatically to collect these failures.

Example (log):

[W2024-12-31T01:20:55.752718Z 2562581 0 json_subtract.go:121] Unknown fields while parsing property namespace "": {"env":{}, "is_google":false, "mode":0}
2024/12/31 01:20:55 run starting
2024/12/31 01:21:06 installed tools
[E2024-12-31T01:37:02.689566Z 2562581 0 errors.go:128] set status: FAILURE: failed to run test golang.org/x/tools module: exit status 123
failed to run test golang.org/x/tools/gopls/doc/assets module: fork/exec /home/swarming/.swarming/w/ir/cache/tools/bin/rdb: input/output error
failed to run test golang.org/x/tools/gopls module: fork/exec /home/swarming/.swarming/w/ir/cache/tools/bin/rdb: input/output error
  with SummaryMarkdown:
* go on release-branch.go1.22 ([commit 8f3f22e](https://go.googlesource.com/go/+/8f3f22eef807250155301822a8960afec160cc02))
* tools on master ([commit 4f820db](https://go.googlesource.com/tools/+/4f820dbaf9859eaafa01a17d133583f4d8c5a73c))

[Build or test failure, click here for results.](https://ci.chromium.org/ui/inv/build-8727080158692716497)

To reproduce, try `gomote repro 8727080158692716497`.

Additional links for debugging:
* [Output for test golang.org/x/tools module](https://logs.chromium.org/logs/golang/buildbucket/cr-buildbucket/8727080158692716497/+/u/step/19/log/2)
* [Output for test golang.org/x/tools/gopls/doc/assets module](https://logs.chromium.org/logs/golang/buildbucket/cr-buildbucket/8727080158692716497/+/u/step/20/log/2)
* [Output for test golang.org/x/tools/gopls module](https://logs.chromium.org/logs/golang/buildbucket/cr-buildbucket/8727080158692716497/+/u/step/21/log/2)

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- builder == "x_tools-go1.22-linux-riscv64" && repo == "tools" && mode == "build"

2024-12-31 00:04 x_tools-go1.22-linux-riscv64 tools@4f820dba release-branch.go1.22@8f3f22ee [build] (log)

[W2024-12-31T01:20:55.752718Z 2562581 0 json_subtract.go:121] Unknown fields while parsing property namespace "": {"env":{}, "is_google":false, "mode":0}
2024/12/31 01:20:55 run starting
2024/12/31 01:21:06 installed tools
[E2024-12-31T01:37:02.689566Z 2562581 0 errors.go:128] set status: FAILURE: failed to run test golang.org/x/tools module: exit status 123
failed to run test golang.org/x/tools/gopls/doc/assets module: fork/exec /home/swarming/.swarming/w/ir/cache/tools/bin/rdb: input/output error
failed to run test golang.org/x/tools/gopls module: fork/exec /home/swarming/.swarming/w/ir/cache/tools/bin/rdb: input/output error
  with SummaryMarkdown:
* go on release-branch.go1.22 ([commit 8f3f22e](https://go.googlesource.com/go/+/8f3f22eef807250155301822a8960afec160cc02))
* tools on master ([commit 4f820db](https://go.googlesource.com/tools/+/4f820dbaf9859eaafa01a17d133583f4d8c5a73c))

[Build or test failure, click here for results.](https://ci.chromium.org/ui/inv/build-8727080158692716497)

To reproduce, try `gomote repro 8727080158692716497`.

Additional links for debugging:
* [Output for test golang.org/x/tools module](https://logs.chromium.org/logs/golang/buildbucket/cr-buildbucket/8727080158692716497/+/u/step/19/log/2)
* [Output for test golang.org/x/tools/gopls/doc/assets module](https://logs.chromium.org/logs/golang/buildbucket/cr-buildbucket/8727080158692716497/+/u/step/20/log/2)
* [Output for test golang.org/x/tools/gopls module](https://logs.chromium.org/logs/golang/buildbucket/cr-buildbucket/8727080158692716497/+/u/step/21/log/2)

— watchflakes