Constexpr attacks (pext only)

LLR: 2.97 (-2.94,2.94) <0.00,2.00>
Total: 38400 W: 10057 L: 9749 D: 18594
Ptnml(0-2): 93, 4110, 10498, 4394, 105
https://tests.stockfishchess.org/tests/view/69d2073261a12cebe17edc04

compile time generation leads to sharing tables through the binary, resulting
in gain on fishtest, as well as reduced memory usage. The downside is slightly
longer compilation time.

Using pdep reduces table size 4x, and gains a little outside of fishtest as well.

closes https://github.com/official-stockfish/Stockfish/pull/6706

No functional change

src/types.h

@@ -87,8 +87,7 @@
     #if defined(USE_PEXT)
         #include <immintrin.h>  // Header for _pext_u64() intrinsic
         #define pext(b, m) _pext_u64(b, m)
-    #else
-        #define pext(b, m) 0
+        #define pdep(b, m) _pdep_u64(b, m)
     #endif
 
 namespace Stockfish {