Fix env vars for helix

Author: HaoK

eng/helix/vstest/runtests.cmd

@@ -4,10 +4,10 @@ set runtimeVersion=%3
 powershell.exe -NoProfile -ExecutionPolicy unrestricted -Command "[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; &([scriptblock]::Create((Invoke-WebRequest -useb 'https://dot.net/v1/dotnet-install.ps1'))) -Version %sdkVersion% -InstallDir %HELIX_CORRELATION_PAYLOAD%\sdk"
 powershell.exe -NoProfile -ExecutionPolicy unrestricted -Command "[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; &([scriptblock]::Create((Invoke-WebRequest -useb 'https://dot.net/v1/dotnet-install.ps1'))) -Runtime dotnet -Version %runtimeVersion% -InstallDir %HELIX_CORRELATION_PAYLOAD%\sdk"
 set DOTNET_SKIP_FIRST_TIME_EXPERIENCE=1
-set DOTNET_ROOT="$HELIX_CORRELATION_PAYLOAD/sdk"
-set PATH="$DOTNET_ROOT:$PATH"
+set DOTNET_ROOT=%HELIX_CORRELATION_PAYLOAD%/sdk
+set PATH=$DOTNET_ROOT:$PATH
 set DOTNET_MULTILEVEL_LOOKUP=0
-set DOTNET_CLI_HOME="$HELIX_CORRELATION_PAYLOAD/home"
+set DOTNET_CLI_HOME=%HELIX_CORRELATION_PAYLOAD%/home
 set helix=true
 %HELIX_CORRELATION_PAYLOAD%\sdk\dotnet vstest %target% --logger:trx