Ensure cache supporting files still exist after --cache-clear

Fix pytest-dev#6290

changelog/6290.bugfix.rst

@@ -0,0 +1 @@
+The supporting files in the ``.pytest_cache`` directory will be properly restored after running ``--cache-clear``.

src/_pytest/cacheprovider.py

@@ -49,7 +49,6 @@ def for_config(cls, config):
         cachedir = cls.cache_dir_from_config(config)
         if config.getoption("cacheclear") and cachedir.exists():
             rm_rf(cachedir)
-            cachedir.mkdir()
         return cls(cachedir, config)
 
     @staticmethod

testing/test_cacheprovider.py

@@ -270,6 +270,7 @@ def test_3(): assert 0
         )
         result = testdir.runpytest(str(p), "--lf", "--cache-clear")
         result.stdout.fnmatch_lines(["*1 failed*2 passed*"])
+        assert testdir.tmpdir.join(".pytest_cache", "README.md").isfile()
 
         # Run this again to make sure clear-cache is robust
         if os.path.isdir(".pytest_cache"):