fa85c985ed qa: Add p2p_invalid_locator test (MarcoFalke)
Pull request description:
Should not be merged *before* #13907
Tree-SHA512: a67ca407854c421ed20a184d0b0dc90085aed3e3431d9652a107fa3022244767e67f67e50449b7e95721f56906836b134615875f28a21e8a012eb22cfe6a66a5