Import on Windows with Gitfs with function file.normpath fails with TemplateNotFound error

Description of Issue

TemplateNotFound error whith Windows + gitfs when I use import with the function file.normpath.

Note that gitfs.py seems to use also file.normpath and I have the same kind of issue here: #54110
https://github.com/saltstack/salt/blob/9b0331c0c8e26b0442e11e69670ef0401611b8b0/salt/utils/gitfs.py#L2866

Setup

Use import like this one:

{%- from salt['file.normpath'](tpldir ~ '/../map.jinja') import vscode with context %}

Workaround found like this

{%- from salt['file.normpath'](tpldir ~ '/../map.jinja').replace('\\', '/') import vscode with context %}

Steps to Reproduce Issue

1. Have a Windows OS
2. Configure Gitfs
3. Configure an import with function file.normpath like this example

{%- from salt['file.normpath'](tpldir ~ '/../map.jinja') import xxx with context %}

4. Clear the cache

C:\salt\bin\python.exe C:\salt\bin\Scripts\salt-call saltutil.clear_cache
[ERROR   ] Attempt to clear cache with saltutil.clear_cache FAILED with: [WinError 5] Accès refusé: 'c:\\salt\\var\\cache\\salt\\minion\\gitfs\\d189884602febd6b283b53aeac85ef83062e4ed2836b6c13ea88bfc036b18633\\.git\\objects\\pack\\pack-1d3fb07243a3b4fe233d8c8caa341ebe160f36ae.idx'
local:
    False

Note that I have an error each time that I use this command on Windows and I delete manually all file inside the folder C:\salt\var\cache\salt\minion\gitfs.

5. When I run the state.apply Ihave the following error:

[...]
---
[CRITICAL] Rendering SLS 'base:salt/vscode/install.pkg' failed: Jinja error: salt\vscode\map.jinja
Traceback (most recent call last):
  File "C:\salt\bin\lib\site-packages\salt\utils\templates.py", line 392, in render_jinja_tmpl
    output = template.render(**decoded_context)
  File "C:\salt\bin\lib\site-packages\jinja2\environment.py", line 1008, in render
    return self.environment.handle_exception(exc_info, True)
  File "C:\salt\bin\lib\site-packages\jinja2\environment.py", line 780, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "C:\salt\bin\lib\site-packages\jinja2\_compat.py", line 37, in reraise
    raise value.with_traceback(tb)
  File "<template>", line 1, in top-level template code
  File "C:\salt\bin\lib\site-packages\salt\utils\jinja.py", line 171, in get_source
    raise TemplateNotFound(template)
jinja2.exceptions.TemplateNotFound: salt\vscode\map.jinja

; line 1

---
{%- from salt['file.normpath'](tpldir ~ '/../map.jinja') import vscode with context %}    <======================

I think this is because the function file.normpath use backslash with gitfs instead of slash.

6. Replace the previous import with the full path like this

{%- from 'salt/vscode/map.jinja' import vscode with context %}

This time I have no error

7. Now update again the import that provide the error

{%- from salt['file.normpath'](tpldir ~ '/../map.jinja') import vscode with context %}

And now it works... I think this is because all dirs in the cache have been created with the previous success of state.apply

Workaround without these steps:

1. This time use this import that replace backslash by slash:

{%- from salt['file.normpath'](tpldir ~ '/../map.jinja').replace('\\', '/') import vscode with context %}

2. Clear the cache

PS C:\WINDOWS\system32> C:\salt\bin\python.exe C:\salt\bin\Scripts\salt-call saltutil.clear_cache
[ERROR   ] Attempt to clear cache with saltutil.clear_cache FAILED with: [WinError 5] Accès refusé: 'c:\\salt\\var\\cache\\salt\\minion\\gitfs\\d189884602febd6b283b53aeac85ef83062e4ed2836b6c13ea88bfc036b18633\\.git\\objects\\pack\\pack-b96f37be7a8cec1bb53f7d4d39d90d5cbaf2ceb8.idx'
local:
    False

3. the state.apply works

Versions Report

PS C:\WINDOWS\system32> C:\salt\bin\python.exe C:\salt\bin\Scripts\salt-call --versions-report
Salt Version:
           Salt: 2019.2.0

Dependency Versions:
           cffi: 1.11.5
       cherrypy: 17.4.1
       dateutil: 2.7.5
      docker-py: Not Installed
          gitdb: 2.0.5
      gitpython: 2.1.10
          ioflo: Not Installed
         Jinja2: 2.10
        libgit2: 0.28.2
        libnacl: 1.6.1
       M2Crypto: Not Installed
           Mako: 1.0.7
   msgpack-pure: Not Installed
 msgpack-python: 0.5.6
   mysql-python: Not Installed
      pycparser: 2.17
       pycrypto: 2.6.1
   pycryptodome: Not Installed
         pygit2: 0.28.2
         Python: 3.5.4 (v3.5.4:3f56838, Aug  8 2017, 02:17:05) [MSC v.1900 64 bit (AMD64)]
   python-gnupg: 0.4.3
         PyYAML: 3.13
          PyZMQ: 17.1.2
           RAET: Not Installed
          smmap: 2.0.5
        timelib: 0.2.4
        Tornado: 4.5.3
            ZMQ: 4.2.5

System Versions:
           dist:
         locale: cp1252
        machine: AMD64
        release: 10
         system: Windows
        version: 10 10.0.18362 SP0 Multiprocessor Free

Start with salt/utils/gitfs.py around line 2866, then trace the rendering path through salt/utils/templates.py and salt/utils/jinja.py. Reproduce the Windows gitfs setup with the file.normpath import, clear the cache, and run state.apply; done means the import succeeds from a clean cache without TemplateNotFound.