Include Performance Cores only in default affinity mask

[hvlad]

Some modern CPU's could contain two set of cores - Efficient (E) and Performance (P).
By default Firebird runs on all available cores. Many times I saw significant performance drop in this (default) case.
Setting affinity mask to exclude E-cores restore performance to the expected level. More, I see the same problem not
only with Firebird, for example Firebird build runs near 3 times slower when E-cores are used on my i7-12700 CPU (8P + 4E).
So far this problem was not confirmed on non-Windows OS. Note, CpuAffinityMask is implemented on Windows only.

I offer to exclude E-cores when affinity mask is not set, i.e. by default.