fa3745bda84d5b3a26fdf8af4ac44d6088e11eee qa: Add tests for invalid message headers (MarcoFalke)
Pull request description:
Tree-SHA512: b37e297cfd65a33a7af201f750a303cf437b438e40d38b1d2f562ccde67082616daa110ca1e5e3af6514ea4ca4b115362acf2ffa6263cea3c8e8189ce02dda67
Backport of Core PR15246