Add a standardized benchmark command speedtest.

`speedtest [threads] [hash_MiB] [time_s]`. `threads` default to system concurrency. `hash_MiB` defaults to `threads*128`. `time_s` defaults to 150.

Intended to be used with default parameters, as a stable hardware benchmark.

Example:
```
C:\dev\stockfish-master\src>stockfish.exe speedtest
Stockfish dev-20240928-nogit by the Stockfish developers (see AUTHORS file)
info string Using 16 threads
Warmup position 3/3
Position 258/258
===========================
Version                    : Stockfish dev-20240928-nogit
Compiled by                : g++ (GNUC) 13.2.0 on MinGW64
Compilation architecture   : x86-64-vnni256
Compilation settings       : 64bit VNNI BMI2 AVX2 SSE41 SSSE3 SSE2 POPCNT
Compiler __VERSION__ macro : 13.2.0
Large pages                : yes
User invocation            : speedtest
Filled invocation          : speedtest 16 2048 150
Available processors       : 0-15
Thread count               : 16
Thread binding             : none
TT size [MiB]              : 2048
Hash max, avg [per mille]  :
    single search          : 40, 21
    single game            : 631, 428
Total nodes searched       : 2099917842
Total search time [s]      : 153.937
Nodes/second               : 13641410
```

-------------------------------

Small unrelated tweaks:
 - Network verification output is now handled as a callback.
 - TT hashfull queries allow specifying maximum entry age.

closes https://github.com/official-stockfish/Stockfish/pull/5354

No functional change

src/misc.h

@@ -28,6 +28,7 @@
 #include <iosfwd>
 #include <optional>
 #include <string>
+#include <string_view>
 #include <vector>
 
 #define stringify2(x) #x
@@ -35,6 +36,7 @@
 
 namespace Stockfish {
 
+std::string engine_version_info();
 std::string engine_info(bool to_uci = false);
 std::string compiler_info();
 
@@ -79,8 +81,8 @@ inline TimePoint now() {
       .count();
 }
 
-inline std::vector<std::string> split(const std::string& s, const std::string& delimiter) {
-    std::vector<std::string> res;
+inline std::vector<std::string_view> split(std::string_view s, std::string_view delimiter) {
+    std::vector<std::string_view> res;
 
     if (s.empty())
         return res;
@@ -102,7 +104,7 @@ inline std::vector<std::string> split(const std::string& s, const std::string& d
 }
 
 void remove_whitespace(std::string& s);
-bool is_whitespace(const std::string& s);
+bool is_whitespace(std::string_view s);
 
 enum SyncCout {
     IO_LOCK,