de23739b22 test: Fix rpc_net.py "pong" race condition (Ben Woosley)
Pull request description:
Prior to this change, the test fails with KeyError if pong has
a zero value at the time this is called, as getpeerinfo's
bytesrecv_per_msg result excludes zero-values.
Combined these to a single wait_until as well, which will be a bit more
forgiving re the timeout while still enforcing the same 2 seconds
overall.
https://ci.appveyor.com/project/DrahtBot/bitcoin/builds/21310881#L62
Tree-SHA512: dc60f95a0e139c104fd81c8a7e0c9b3c25907de26c9d4e5976ae490e8ed5db0f0c492cd0e996ef6b5eb02cae82a62d4551ed36f95601871b19472050b3247bc0
Backport Core PR15069