test: be less eager to set up the build environment

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Library/Homebrew/cmd/test.rb

@@ -2,13 +2,13 @@ require 'extend/ENV'
 require 'hardware'
 require 'keg'
 
-ENV.extend(HomebrewEnvExtension)
-ENV.setup_build_environment
-
 module Homebrew extend self
   def test
     raise FormulaUnspecifiedError if ARGV.named.empty?
 
+    ENV.extend(HomebrewEnvExtension)
+    ENV.setup_build_environment
+
     ARGV.formulae.each do |f|
       # Cannot test uninstalled formulae
       unless f.installed?