Remove more unused requires

Library/Homebrew/cmd/--env.rb

@@ -1,5 +1,4 @@
-require 'extend/ENV'
-require 'hardware'
+require "extend/ENV"
 
 module Homebrew
   def __env

Library/Homebrew/cmd/postinstall.rb

@@ -1,5 +1,3 @@
-require 'formula_installer'
-
 module Homebrew
   def postinstall
     ARGV.formulae.each {|f| f.post_install }

Library/Homebrew/cmd/test.rb

@@ -1,7 +1,5 @@
-require 'extend/ENV'
-require 'hardware'
-require 'keg'
-require 'timeout'
+require "extend/ENV"
+require "timeout"
 
 module Homebrew
   TEST_TIMEOUT_SECONDS = 5*60

Library/Homebrew/cmd/versions.rb

@@ -1,4 +1,3 @@
-require "formula"
 require "formula_versions"
 
 module Homebrew

Library/Homebrew/formula_versions.rb

@@ -1,3 +1,5 @@
+require "formula"
+
 class FormulaVersions
   IGNORED_EXCEPTIONS = [
     ArgumentError, NameError, SyntaxError, TypeError,