x/telemetry/cmd/stacks: spurious git SIGKILL in tests

[gopherbot]

#!watchflakes
default <- pkg == "golang.org/x/telemetry/cmd/stacks" && output ~ `checking out.*killed`

Issue created automatically to collect these failures.

Example (log):

=== RUN   TestReadPCLineTable/gopls
2025/09/05 08:58:37 cloning tools@gopls/v0.16.1
    stacks_test.go:66: readPCLineTable got err clone: checking out https://go.googlesource.com/tools: signal: killed
        hint: Using 'master' as the name for the initial branch. This default branch name
        hint: is subject to change. To configure the initial branch name to use in all
        hint: of your new repositories, which will suppress this warning, call:
        hint: 
        hint: 	git config --global init.defaultBranch <name>
        hint: 
        hint: Names commonly chosen instead of 'master' are 'main', 'trunk' and
        hint: 'development'. The just-created branch can be renamed via this command:
        hint: 
        hint: 	git branch -m <name>
        Initialized empty Git repository in /Users/swarming/.swarming/w/ir/x/t/TestReadPCLineTablegopls3840399851/001/v0.16.1/.git/
        From https://go.googlesource.com/tools
         * tag               gopls/v0.16.1 -> FETCH_HEAD
         want nil
--- FAIL: TestReadPCLineTable/gopls (67.84s)

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "golang.org/x/telemetry/cmd/stacks" && test == "TestReadPCLineTable/gopls"

2025-09-05 15:19 x_telemetry-go1.24-darwin-amd64-longtest telemetry@af835b03 release-branch.go1.24@d41a8222 x/telemetry/cmd/stacks.TestReadPCLineTable/gopls (log)

=== RUN   TestReadPCLineTable/gopls
2025/09/05 08:58:37 cloning tools@gopls/v0.16.1
    stacks_test.go:66: readPCLineTable got err clone: checking out https://go.googlesource.com/tools: signal: killed
        hint: Using 'master' as the name for the initial branch. This default branch name
        hint: is subject to change. To configure the initial branch name to use in all
        hint: of your new repositories, which will suppress this warning, call:
        hint: 
        hint: 	git config --global init.defaultBranch <name>
        hint: 
        hint: Names commonly chosen instead of 'master' are 'main', 'trunk' and
        hint: 'development'. The just-created branch can be renamed via this command:
        hint: 
        hint: 	git branch -m <name>
        Initialized empty Git repository in /Users/swarming/.swarming/w/ir/x/t/TestReadPCLineTablegopls3840399851/001/v0.16.1/.git/
        From https://go.googlesource.com/tools
         * tag               gopls/v0.16.1 -> FETCH_HEAD
         want nil
--- FAIL: TestReadPCLineTable/gopls (67.84s)

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "golang.org/x/telemetry/cmd/stacks" && test == "TestReadPCLineTable/gopls"

2025-10-08 14:25 x_telemetry-gotip-darwin-amd64-longtest telemetry@badf71c6 go@4837fbe4 x/telemetry/cmd/stacks.TestReadPCLineTable/gopls (log)

=== RUN   TestReadPCLineTable/gopls
2025/10/09 01:29:14 cloning tools@gopls/v0.16.1
    stacks_test.go:66: readPCLineTable got err clone: checking out https://go.googlesource.com/tools: signal: killed
        hint: Using 'master' as the name for the initial branch. This default branch name
        hint: is subject to change. To configure the initial branch name to use in all
        hint: of your new repositories, which will suppress this warning, call:
        hint: 
        hint: 	git config --global init.defaultBranch <name>
        hint: 
        hint: Names commonly chosen instead of 'master' are 'main', 'trunk' and
        hint: 'development'. The just-created branch can be renamed via this command:
        hint: 
        hint: 	git branch -m <name>
        Initialized empty Git repository in /Users/swarming/.swarming/w/ir/x/t/TestReadPCLineTablegopls2496382232/001/v0.16.1/.git/
        From https://go.googlesource.com/tools
         * tag               gopls/v0.16.1 -> FETCH_HEAD
         want nil
--- FAIL: TestReadPCLineTable/gopls (105.13s)

— watchflakes