let tests pass on Xcode-only systems

Closes Homebrew/homebrew#42976.

Library/Homebrew/test/test_integration_cmds.rb

@@ -65,7 +65,7 @@ class IntegrationCommandTests < Homebrew::TestCase
   end
 
   def test_env
-    assert_match "CMAKE_PREFIX_PATH=\"#{HOMEBREW_PREFIX}\"",
+    assert_match /CMAKE_PREFIX_PATH="#{HOMEBREW_PREFIX}[:"]/,
                  cmd("--env")
   end