Fix pyenv-latest to ignore virtualenvs

[native-api]

Make sure you have checked all steps below.

Prerequisite

• Please consider implementing the feature as a hook script or plugin as a first step.
  • pyenv has some powerful support for plugins and hook scripts. Please refer to Authoring plugins for details and try to implement it as a plugin if possible.
• Please consider contributing the patch upstream to rbenv, since we have borrowed most of the code from that project.
  • We occasionally import the changes from rbenv. In general, you can expect changes made in rbenv will be imported to pyenv too, eventually.
  • Generally speaking, we prefer not to make changes in the core in order to keep compatibility with rbenv.
• My PR addresses the following pyenv issue (if any)
  • Workaround for Support hooks in pyenv-latest to allow for virtualenvs #2606

Description

• Here are some details about my PR

When there are virtualenvs, pyenv-latest erroneously searches them for prefix resolution, too:

$ echo $PYENV_VERSION
pypy2.7-7
$ pyenv versions
  system
  3.10.9
  3.10.9/envs/venv
  3.11-dev
  pypy2.7-7.3.11
* pypy2.7-7.3.11/envs/venvpypy (set by PYENV_VERSION environment variable)
  venv
  venvpypy

Tests

• My PR adds the following unit tests (if any)

Test for ignoring specific entry types