[glib] (6 commits) ...Merge branch 'mcatanzaro/#2597' into 'main'

[Philip Withnall <pwithnall src gnome org>]

Summary of changes:

  4667f59... proxy-test: fix check for simple:// URI scheme (*)
  8a1f087... gsimpleproxyresolver: default_proxy should be consistently  (*)
  6f83f45... gsimpleproxyresolver: ensure default proxy is valid (*)
  1738fad... proxyaddressenumerator: set error parameter more thoughtful (*)
  8e29865... gproxyresolver: add asserts to ensure error is set (*)
  164d375... Merge branch 'mcatanzaro/#2597' into 'main'

(*) This commit already existed in another branch; no separate mail sent