Try using dump folder

Author: HaoK

eng/helix/content/runtests.cmd

@@ -24,7 +24,7 @@ set DOTNET_ROOT=%DOTNET_HOME%\%$arch%
 set DOTNET_SKIP_FIRST_TIME_EXPERIENCE=1
 set DOTNET_MULTILEVEL_LOOKUP=0
 set DOTNET_CLI_HOME=%HELIX_CORRELATION_PAYLOAD%\home
-set VSTEST_DUMP_PATH=%HELIX_WORKITEM_UPLOAD_ROOT%
+set VSTEST_DUMP_PATH=%HELIX_DUMP_FOLDER%
 
 set "PATH=%DOTNET_ROOT%;%PATH%;%HELIX_CORRELATION_PAYLOAD%\node\bin"
 echo Set path to: "%PATH%"