Update for Miri error text changes

Author: shepmaster

tests/spec/features/tools_spec.rb

@@ -42,8 +42,7 @@ def code_with_lint_warnings
     in_tools_menu { click_on("Miri") }
 
     within(:output, :stderr) do
-      expect(page).to have_content %r{pointer must be in-bounds at offset 1, but is outside bounds of alloc\d+ which has size 0}, wait: 10
-
+      expect(page).to have_content %r{alloc\d+ has size 0, so pointer to 1 byte starting at offset 0 is out-of-bounds}, wait: 10
     end
   end