Failures when running init poison and binary scan in parallel

[ViktorHofer]

  Build Mode: source-build
  Build Environment: x64 Release linux centos.9-x64
  Crossgen is disabled due to incompatibility with poison checks.
  BinaryToolKit -> /__w/1/s/artifacts/bin/BinaryToolKit/Release/BinaryToolKit.dll
  Microsoft.DotNet.UnifiedBuild.Tasks -> /__w/1/s/artifacts/bin/Microsoft.DotNet.UnifiedBuild.Tasks/Release/Microsoft.DotNet.UnifiedBuild.Tasks.dll
  Starting binary tool at 06/11/2025 04:47:32 in Validate mode
  Detecting binaries in '/__w/1/s' not listed in '/__w/1/s/eng/allowed-vmr-binaries.txt'...
  Microsoft.DotNet.SourceBuild.Tasks.LeakDetection -> /__w/1/s/artifacts/bin/Microsoft.DotNet.SourceBuild.Tasks.LeakDetection/Release/Microsoft.DotNet.SourceBuild.Tasks.LeakDetection.dll
  [04:47:32.76] Poisoning existing packages for leak detection.
/__w/1/s/eng/init-detect-binaries.proj(22,5): error : The process cannot access the file '/__w/1/s/prereqs/packages/previously-source-built/Microsoft.CodeAnalysis.VisualBasic.Workspaces.5.0.0-1.25302.104.nupkg' because it is being used by another process.
##[error]eng/init-detect-binaries.proj(22,5): error : (NETCORE_ENGINEERING_TELEMETRY=Build) The process cannot access the file '/__w/1/s/prereqs/packages/previously-source-built/Microsoft.CodeAnalysis.VisualBasic.Workspaces.5.0.0-1.25302.104.nupkg' because it is being used by another process.
  [04:48:31.85] Done poisoning.

from https://dev.azure.com/dnceng/internal/_build/results?buildId=2727614&view=logs&j=2efcdee0-63a0-5f4c-6890-20d889251d12&t=687ca494-57d2-542a-c494-988bec6c615f&s=9b073b6c-199e-5782-2adb-83c30ea48e21 (retry 1)

cc @ellahathaway