Enable optimized single-proc allocation helpers for single-proc x86/x64 systems only (#27014)
Enable optimized single-proc allocation helpers for single-proc x86/x64 systems only (#27014)

Use maximum number of processors the process may run on to determine whether it is ok to use
single-proc allocation helpers. It is not sufficient to depend on current process affinity since
that can change during the process lifetime.

Also, the single-proc allocation helpers work well on x86/x64 systems only because of they depend
on atomic non-interlocked increment instruction for good performance. Such instruction is available
on x86/x64 only. Disable them everywhere else.

Fixes #26990
cshung/coreclr,cshung/coreclr,krk/coreclr,poizan42/coreclr,krk/coreclr,krk/coreclr,poizan42/coreclr,krk/coreclr,poizan42/coreclr,cshung/coreclr,poizan42/coreclr,cshung/coreclr,poizan42/coreclr,poizan42/coreclr,krk/coreclr,cshung/coreclr,krk/coreclr,cshung/coreclr