Fix the abc_p2p_avalanche functional tests for ARM
Fix the abc_p2p_avalanche functional tests for ARM

Summary:
The test is failing on slow machines, especially when using qemu (ARM
and AArch64).

Test Plan:
  ninja check-functional
  ./contrib/teamcity/build-configurations.py buld-linux-arm
  ./contrib/teamcity/build-configurations.py buld-linux-aarch64

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D9347

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