fix for python 3.8 from microsoft store failing to add new venv (micr…

…osoft#6086)

* fix for python 3.8 from microsoft store failing to add new venv

new versions of python >= 3.8 from the windows store have a different executable name (ie. python3.8.exe) in the registry InstallPath, compared to what is in the venv folder (python.exe) so search for both if interpExe is not found.

Fix microsoft#6082

* minor refactor

Python/Product/PythonTools/PythonTools/Environments/VirtualEnv.cs

@@ -405,8 +405,11 @@ IInterpreterRegistryService service
             interpExe = Path.GetFileName(baseInterpreter.Configuration.InterpreterPath);
             winterpExe = Path.GetFileName(baseInterpreter.Configuration.GetWindowsInterpreterPath());
             var scripts = new[] { "Scripts", "bin" };
-            interpExe = PathUtils.FindFile(prefixPath, interpExe, firstCheck: scripts);
-            winterpExe = PathUtils.FindFile(prefixPath, winterpExe, firstCheck: scripts);
+
+            // new versions of python >= 3.8 from the windows store have a different executable name (ie. python3.8.exe) in the 
+            // registry InstallPath, compared to what is in the venv folder (python.exe) so search for both if interpExe is not found.
+            interpExe = PathUtils.FindFile(prefixPath, interpExe, firstCheck: scripts) ?? PathUtils.FindFile(prefixPath, "python.exe", firstCheck: scripts);
+            winterpExe = PathUtils.FindFile(prefixPath, winterpExe, firstCheck: scripts) ?? PathUtils.FindFile(prefixPath, "pythonw.exe", firstCheck: scripts);
             pathVar = baseInterpreter.Configuration.PathEnvironmentVariable;
         }