(PUP-7126) Add pre_resource_eval in POSIX file provider

This commit adds pre_reosurce_eval to the POSIX file provider. This function is
a class function that when called & when SELinux is supported, will setup and
create a SELinux handle. More information about this function can be found in
this PR: #9376.

lib/puppet/provider/file/posix.rb

@@ -12,8 +12,21 @@
   require 'etc'
   require_relative '../../../puppet/util/selinux'
 
-  def self.post_resource_eval
-    Selinux.matchpathcon_fini if Puppet::Util::SELinux.selinux_support?
+  class << self
+    # @return [non-NULL handle value] A handle for selinux
+    attr_reader :selinux_handle
+
+    def pre_resource_eval
+      @selinux_handle = if Puppet::Util::SELinux.selinux_support?
+                          Selinux.selabel_open(0, nil, 0)
+                        else
+                          nil
+                        end
+    end
+
+    def self.post_resource_eval
+      Selinux.matchpathcon_fini if Puppet::Util::SELinux.selinux_support?
+    end
   end
 
   def uid2name(id)