Windows specific path issues flares up on Tests on Linux

[xingh]

All 7 failures are environment artifacts of this Linux sandbox, not product regressions: 2 LSP tests assert Windows-style C:\ → file:///C:/ path conversion (running on Linux), 3 agent tests fail with "Pipe is broken" because the sandbox blocks the child-process spawning they need, and 2 runtime tests (LocalArtifactStoreTests.GetAccessUrl_ReturnsFileUri, CodeGraderTests.Command_With_OutputFile_Substitution) fail for the same environmental reasons.

[ramseur]

Acknowledged will review files