Merge bitcoin#29667: fuzz: actually test garbage >64b in p2p transpor…

…t test

626f8e3 fuzz: actually test garbage >64b in p2p transport test (Pieter Wuille)

Pull request description:

  This fixes an oversight from bitcoin#28196: in the `p2p_transport_bidirectional_v2` fuzz test, when the desired garbage length is over 64 bytes, the code would actually use garbage length 0. Fix this.

ACKs for top commit:
  instagibbs:
    ACK bitcoin@626f8e3
  brunoerg:
    crACK 626f8e3

Tree-SHA512: f6346367adb10464b6c9d20aef43625531d2a4d8110887ad03214b8c1907b83560f2dd5b5415e2180a40b4cd276d51881b32b60c740471b5c6bb218aa19848d8

src/test/fuzz/p2p_transport_serialization.cpp

@@ -349,6 +349,7 @@ std::unique_ptr<Transport> MakeV2Transport(NodeId nodeid, bool initiator, RNG& r
     } else {
         // If it's longer, generate it from the RNG. This avoids having large amounts of
         // (hopefully) irrelevant data needing to be stored in the fuzzer data.
+        garb.resize(garb_len);
         for (auto& v : garb) v = uint8_t(rng());
     }
     // Retrieve entropy