Fix Unity project path in windows standalone build script

dist/platforms/windows/run_tests.ps1

@@ -67,24 +67,24 @@ foreach ( $platform in ${env:TEST_PLATFORMS}.Split(";") )
         Write-Output ""
 
         # Create directories if they do not exist
-        if(-Not (Test-Path -Path $Env:UNITY_PROJECT_PATH\Assets\Editor))
+        if(-Not (Test-Path -Path $UNITY_PROJECT_PATH\Assets\Editor))
         {
             # We use -Force to suppress output, doesn't overwrite anything
-            New-Item -ItemType Directory -Force -Path $Env:UNITY_PROJECT_PATH\Assets\Editor
+            New-Item -ItemType Directory -Force -Path $UNITY_PROJECT_PATH\Assets\Editor
         }
-        if(-Not (Test-Path -Path $Env:UNITY_PROJECT_PATH\Assets\Player))
+        if(-Not (Test-Path -Path $UNITY_PROJECT_PATH\Assets\Player))
         {
             # We use -Force to suppress output, doesn't overwrite anything
             New-Item -ItemType Directory -Force -Path $Env:UNITY_PROJECT_PATH\Assets\Player
         }
 
         # Copy the scripts
-        Copy-Item -Path "c:\UnityStandaloneScripts\Assets\Editor" -Destination $Env:UNITY_PROJECT_PATH\Assets\Editor -Recurse
-        Copy-Item -Path "c:\UnityStandaloneScripts\Assets\Player" -Destination $Env:UNITY_PROJECT_PATH\Assets\Player -Recurse
+        Copy-Item -Path "c:\UnityStandaloneScripts\Assets\Editor" -Destination $UNITY_PROJECT_PATH\Assets\Editor -Recurse
+        Copy-Item -Path "c:\UnityStandaloneScripts\Assets\Player" -Destination $UNITY_PROJECT_PATH\Assets\Player -Recurse
 
         # Verify recursive paths
-        Get-ChildItem -Path $Env:UNITY_PROJECT_PATH\Assets\Editor -Recurse
-        Get-ChildItem -Path $Env:UNITY_PROJECT_PATH\Assets\Player -Recurse
+        Get-ChildItem -Path $UNITY_PROJECT_PATH\Assets\Editor -Recurse
+        Get-ChildItem -Path $UNITY_PROJECT_PATH\Assets\Player -Recurse
 
         $runTests="-runTests -testPlatform StandaloneWindows64 -builtTestRunnerPath $UNITY_PROJECT_PATH\Build\UnityTestRunner-Standalone.exe"
     }