Use helper module to silence warnings

lib/vagrant/util/platform.rb

@@ -31,9 +31,7 @@ module Vagrant
         def wsl?
           if !defined?(@_wsl)
             @_wsl = false
-            original_verbose = $VERBOSE
-            begin
-              $VERBOSE = nil
+            SilenceWarnings.silence! do
               # Use PATH values to check for `/mnt/c` path indicative of WSL
               if ENV.fetch("PATH", "").downcase.include?("/mnt/c")
                 # Validate WSL via uname output
@@ -42,8 +40,6 @@ module Vagrant
                   @_wsl = true
                 end
               end
-            ensure
-              $VERBOSE = original_verbose
             end
           end
           @_wsl

lib/vagrant/util/which.rb

@@ -29,17 +29,13 @@ module Vagrant
           exts = ENV['PATHEXT'].split(';')
         end
 
-        current_verbose = $VERBOSE
-        $VERBOSE = nil
-        begin
+        SilenceWarnings.silence! do
           ENV['PATH'].encode('UTF-8', 'binary', invalid: :replace, undef: :replace, replace: '').split(File::PATH_SEPARATOR).each do |path|
             exts.each do |ext|
               exe = "#{path}#{File::SEPARATOR}#{cmd}#{ext}"
               return exe if File.executable? exe
             end
           end
-        ensure
-          $VERBOSE = current_verbose
         end
 
         return nil