x/tools/gopls: spurious "connection closed" in mcptools/symbol_references.txt marker test

[adonovan]

Typical symptom (from CL 737000):

=== RUN   Test/mcptools/symbol_references.txt
=== PAUSE Test/mcptools/symbol_references.txt
=== CONT  Test/mcptools/symbol_references.txt
    marker_test.go:2627: go.mod:6:3 (mcptools/symbol_references.txt:13:3): failed to call mcp tool: calling "tools/call": connection closed
    marker_test.go:2627: go.mod:7:3 (mcptools/symbol_references.txt:14:3): failed to call mcp tool: calling "tools/call": connection closed
    marker_test.go:2627: go.mod:8:3 (mcptools/symbol_references.txt:15:3): failed to call mcp tool: calling "tools/call": connection closed
--- FAIL: Test/mcptools/symbol_references.txt (0.36s)

[gabyhelp]

Related Issues

• x/tools/gopls/internal/test/marker: Test/mcptools/search.txt failures #74547 (closed)
• x/tools/gopls/internal/test/marker: Test/*.txt failures #75107
• x/tools/gopls/internal/test/marker: Test/mcptools/symbol_references.txt failures #74536 (closed)
• x/tools/gopls/internal/regtest/marker: TestIdleTimeout failures #63262 (closed)
• x/tools/gopls/internal/test/marker: Test/zeroconfig/dynamicports.txt failures #72022 (closed)
• x/tools/gopls/internal/test/marker: data race in shutdown #74532 (closed)
• x/tools/gopls/internal/test/marker: Test/references/test.txt failures #74529 (closed)
• x/tools/gopls/internal/test/marker: Test/mcptools/outline.txt failures #74512 (closed)
• x/tools/gopls/internal/test/marker: Test/mcptools/diagnostics.txt failures #74503 (closed)
• x/tools/internal/jsonrpc2_v2: test failures with "connection reset by peer" #46520 (closed)

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