our bit_simps shadows Word_Lib bit_simps

[lsf37]

We use a lemma set bit_simps in X64, RISCV64, and AARCH64. In one of the last Isabelle/Word_Lib updates, Florian also introduced a lemma set bit_simps mostly for rules about the test_bit function, which gets shadowed by our name.

We don't really seem to be using the Word_Lib set, so we could just ignore this. Or we could rename to make it slightly less confusing to people who are used to the upstream name.

Any opinions?