Common: use std::chrono for GetLocalTimeSinceJan1970 on Windows

Co-authored-by: Shawn Hoffman <godisgovernment@gmail.com>

Source/Core/Common/Timer.cpp

@@ -7,7 +7,6 @@
 
 #ifdef _WIN32
 #include <Windows.h>
-#include <ctime>
 #include <timeapi.h>
 #else
 #include <sys/time.h>
@@ -68,10 +67,12 @@ u64 Timer::ElapsedMs() const
 
 u64 Timer::GetLocalTimeSinceJan1970()
 {
-  // TODO Would really, really like to use std::chrono here, but Windows did not support
-  // std::chrono::current_zone() until 19H1, and other compilers don't even provide support for
-  // timezone-related parts of chrono. Someday!
-  // see https://bugs.dolphin-emu.org/issues/13007#note-4
+#ifdef _MSC_VER
+  std::chrono::zoned_seconds seconds(
+      std::chrono::current_zone(),
+      std::chrono::time_point_cast<std::chrono::seconds>(std::chrono::system_clock::now()));
+  return seconds.get_local_time().time_since_epoch().count();
+#else
   time_t sysTime, tzDiff, tzDST;
   time(&sysTime);
   tm* gmTime = localtime(&sysTime);
@@ -87,6 +88,7 @@ u64 Timer::GetLocalTimeSinceJan1970()
   tzDiff = sysTime - mktime(gmTime);
 
   return static_cast<u64>(sysTime + tzDiff + tzDST);
+#endif
 }
 
 void Timer::IncreaseResolution()