6e873df347 serfloat: improve/simplify tests (Pieter Wuille)
b45f1f5658 serfloat: do not test encode(bits)=bits anymore (Pieter Wuille)
Pull request description:
Closes#28941.
Our current tests for serfloat verify two distinct properties:
1. Whether they roundtrip `double`->`uint64_t`->`double` (excluding NaN values) on all systems.
2. Whether on systems with a typical floating point unit that encoding matches the hardware representation, as before v22.0, we would dump the hardware representation directly to disk and we wanted to retain compatibility with that.
#28941 seems to show that the second property doesn't always hold, but just for "subnormal" numbers (below $2^{-1021}$). Since we don't care about encoding these numbers, we could exclude such subnormal numbers from the hardware-identical representation test, but this PR goes further and just drops the second property entirely, as I don't think we care about edge-case compatibility with pre-v22.0 code for fee_estimates.dat (the only place it is used).
ACKs for top commit:
glozow:
ACK 6e873df347
fanquake:
ACK 6e873df347 - It's not as much of a priority, but I think we could still backport this.
Tree-SHA512: e18ceee0753a7ee7e999fdfa10b014dc5bb67b6ef79522a0f8c76b889adcfa785772fc26ed7559bcb5a09a9938e243bb54eedd9549bc59080a2c8090155e2267
479ecc0515