resolve http server can't send file large than 2GB (Fix #1290) (#1294)

* resolve problem: http server can't send file large than 2GB.
add unit test for http server send large file.
add /bigobj compile option to msvc x64.

* disable unit test "ServerLargeContentTest" due to out-of-memory on GitHub Actions.

httplib.h

@@ -4691,7 +4691,7 @@ inline ssize_t SocketStream::read(char *ptr, size_t size) {
 inline ssize_t SocketStream::write(const char *ptr, size_t size) {
   if (!is_writable()) { return -1; }
 
-#ifdef _WIN32
+#if defined(_WIN32) && !defined(_WIN64)
   size =
       (std::min)(size, static_cast<size_t>((std::numeric_limits<int>::max)()));
 #endif