Restore _httpContext parameter passed to RequestPhysicalApplicationPath (#732)

* Restore _httpContext parameter passed to RequestPhysicalApplicationPath when called from GetPhysicalPath, lost at #709

* Pass HttpContext property instead of _HttpContext field.

(cherry picked from commit 0e994b0)

Author: claudiamurialdo

dotnet/src/dotnetframework/GxClasses/Core/GXApplication.cs

@@ -2900,7 +2900,7 @@ public string GetPhysicalPath()
 				{
 					if (HttpContext != null)
 					{
-						_physicalPath = RequestPhysicalPath();
+						_physicalPath = RequestPhysicalPath(HttpContext);
 					}
 					else
 					{
@@ -2948,9 +2948,9 @@ public static bool IsHttpContext
 			}
 #endif
 		}
-		private static string RequestPhysicalPath()
+		private static string RequestPhysicalPath(HttpContext httpContext=null)
 		{
-			string phPath = HttpHelper.RequestPhysicalApplicationPath();
+			string phPath = HttpHelper.RequestPhysicalApplicationPath(httpContext);
 			string dirSeparator = Path.DirectorySeparatorChar.ToString();
 			if (!phPath.EndsWith(dirSeparator))
 				return $"{phPath}{dirSeparator}";