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.cpp

@@ -122,7 +122,7 @@ class Logger {
 //
 // For releases (non-dev builds) we only include the version number:
 //      Stockfish version
-std::string engine_info(bool to_uci) {
+std::string engine_version_info() {
     std::stringstream ss;
     ss << "Stockfish " << version << std::setfill('0');
 
@@ -151,11 +151,14 @@ std::string engine_info(bool to_uci) {
 #endif
     }
 
-    ss << (to_uci ? "\nid author " : " by ") << "the Stockfish developers (see AUTHORS file)";
-
     return ss.str();
 }
 
+std::string engine_info(bool to_uci) {
+    return engine_version_info() + (to_uci ? "\nid author " : " by ")
+         + "the Stockfish developers (see AUTHORS file)";
+}
+
 
 // Returns a string trying to describe the compiler we use
 std::string compiler_info() {
@@ -451,7 +454,7 @@ void remove_whitespace(std::string& s) {
     s.erase(std::remove_if(s.begin(), s.end(), [](char c) { return std::isspace(c); }), s.end());
 }
 
-bool is_whitespace(const std::string& s) {
+bool is_whitespace(std::string_view s) {
     return std::all_of(s.begin(), s.end(), [](char c) { return std::isspace(c); });
 }