c4f857cc30 test: Extends wait_for_getheaders so a specific block hash can be checked (Sergi Delgado Segura)
Pull request description:
Fixes https://github.com/bitcoin/bitcoin/issues/18614
Previously, `wait_for_getheaders` would check whether a node had received **any** getheaders message. This implied that, if a test needed to check for a specific block hash within a headers message, it had to make sure that it was checking the desired message. This normally involved having to manually clear `last_message`. This method, apart from being too verbose, was error-prone, given an undesired `getheaders` would make tests pass.
This adds the ability to check for a specific block_hash within the last `getheaders` message.
ACKs for top commit:
achow101:
ACK c4f857cc30
BrandonOdiwuor:
crACK c4f857cc30
cbergqvist:
ACK c4f857cc30
stratospher:
tested ACK c4f857c. went through all getheaders messages sent in the tests and checked that it's the one we want.
Tree-SHA512: afc9a31673344dfaaefcf692ec2ab65958c3d4c005f5f3af525e9960f0622d8246d5311e59aba06cfd5c9e0ef9eb90a7fc8e210f030bfbe67b897c061efdeed1