Try using dump folder

Author: HaoK

eng/helix/content/runtests.sh

@@ -24,7 +24,7 @@ export DOTNET_MULTILEVEL_LOOKUP=0
 export DOTNET_CLI_HOME="$DIR/.home$RANDOM"
 
 export DOTNET_SKIP_FIRST_TIME_EXPERIENCE=1
-export VSTEST_DUMP_PATH=$HELIX_WORKITEM_UPLOAD_ROOT
+export VSTEST_DUMP_PATH=$HELIX_DUMP_FOLDER
 
 RESET="\033[0m"
 RED="\033[0;31m"