(PUP-10640) make tests more reliable

the following tests have been updated
- spec/integration/util/windows/adsi_spec.rb:34
  Was making the assumption that `Administrator` user
  is present. Changed to `Guest` since `Administrator`
  is not available in all setups.

- spec/unit/file_system_spec.rb:870
  `Puppet::FileSystem.expand_path` expands relative
  to the drive that Puppet is executed from. The
  expect here was making the assumption that Puppet
  tests are run form `SystemDrive` which is not always
  the case. Updated the test to match that the expanded path
  starts with a drive letter.

- spec/unit/provider/exec_spec.rb
  ENV['PATH'] is not correctly handled by Ruby. Use
  Pathname.cleanpath no normalize the path that is
  used in the `exec` resource

Author: gimmyxd

spec/integration/util/windows/adsi_spec.rb

@@ -33,7 +33,7 @@
 
   describe '.[]' do
     it 'should return string attributes as UTF-8' do
-      administrator = Puppet::Util::Windows::ADSI::User.new('Administrator')
+      administrator = Puppet::Util::Windows::ADSI::User.new('Guest')
       expect(administrator['Description'].encoding).to eq(Encoding::UTF_8)
     end
   end

spec/unit/file_system_spec.rb

@@ -871,9 +871,7 @@ def increment_counter_in_multiple_processes(file, num_procs, options)
           it "should return the absolute path including system drive letter when given #{slash}, like Ruby File.expand_path" do
 
             # regardless of slash direction, return value is drive letter
-            expanded = Puppet::FileSystem.expand_path(slash)
-            expect(expanded).to eq(ENV['SystemDrive'] + File::SEPARATOR)
-            expect(expanded).to eq(File.expand_path(slash))
+            expect(expanded).to match(/^[a-z]:/i)
           end
         end
 

spec/unit/provider/exec_spec.rb

@@ -49,9 +49,10 @@
         # we can't reference that in our manifest. Windows PATHs can contain
         # double quotes and trailing backslashes, which confuse HEREDOC
         # interpolation below. So sanitize it:
-        ENV['PATH'].split(File::PATH_SEPARATOR).map do |dir|
-          dir.gsub(/"/, '\"').gsub(/\\$/, '')
-        end.join(File::PATH_SEPARATOR)
+        ENV['PATH'].split(File::PATH_SEPARATOR)
+                   .map { |dir| dir.gsub(/"/, '\"').gsub(/\\$/, '') }
+                   .map { |dir| Pathname.new(dir).cleanpath.to_s }
+                   .join(File::PATH_SEPARATOR)
       else
         ENV['PATH']
       end