Add 1GB page support on x86 Linux

1GB pages for the TT give a small performance bump (`./stockfish speedtest 256 32000`):

master:
Nodes/second               : 230514479
patch
Nodes/second               : 237997728

With a large enough TT there is still dTLB thrashing with 2MB pages. 1GB pages reduces that and makes page table walks a bit faster (they're shorter, and there's fewer PTEs, which fits better in cache). `madvise` won't give you huge pages, only large pages, so we use mmap here.

We guard the huge page attempt to x86 + at least 8 huge pages per NUMA node, to avoid memory oversubscription when for example running with a 1.1 GB hash. Additionally, we change the TT clearing slightly so that the pages are better distributed across NUMA nodes.

Data from Torom:

master:
Nodes/second               : 43524292
patch:
Nodes/second               : 44080034

Data on an 8-thread Emerald Rapids VM:

./stockfish speedtest 8 65536

Baseline speedtest (2MB huge pages):

Nodes/second : 7366232
Nodes/second : 7262794
Nodes/second : 7355431
Nodes/second : 7318777

Baseline speedtest (1GB huge pages):

Nodes/second : 7541027
Nodes/second : 7572720
Nodes/second : 7550268
Nodes/second : 7538925

closes https://github.com/official-stockfish/Stockfish/pull/6681

No functional change

src/memory.h

@@ -61,10 +61,13 @@ using AdjustTokenPrivileges_t =
 
 namespace Stockfish {
 
+constexpr size_t HugePageSize = size_t(1) << 30;
+
 void* std_aligned_alloc(size_t alignment, size_t size);
 void  std_aligned_free(void* ptr);
 
 // Memory aligned by page size, min alignment: 4096 bytes
+void* aligned_large_pages_alloc_with_hint(size_t size, bool hugePageHint);
 void* aligned_large_pages_alloc(size_t size);
 void  aligned_large_pages_free(void* mem);