tweak FD_SETSIZE to reduce possibility of UDP timeouts

geez searching 4K sockets most of which are blank...

(cherry picked from commit 39b45e1d57)

llarp/exit/session.cpp

@@ -190,7 +190,7 @@ namespace llarp
       {
         for(auto& item : m_Upstream)
         {
-          auto& queue = item.second;
+          auto& queue = item.second;// XXX: uninitialised memory here!
           while(queue.size())
           {
             auto& msg = queue.front();

llarp/win32/win32_upoll.c

@@ -176,9 +176,6 @@ upoll_ctl(upoll_t* upq, int op, intptr_t fd, upoll_event_t* event)
 int
 upoll_wait_select(upoll_t* upq, upoll_event_t* evs, int nev, int timeout)
 {
-  /* ok we need to test each file descriptor to see whether it is a real file
-   * or a socket. select any file handles (they are always ready)
-   */
   if(nev > FD_SETSIZE)
     nev = FD_SETSIZE;
 

llarp/win32/win32_upoll.h

@@ -29,10 +29,12 @@
 #include <sys/stat.h>
 
 // this is probably big enough to get
-// the lesser of 4096 sockets or whatever
+// the lesser of 96 sockets or whatever
 // the system allows
+// this used to be 4096, but i think
+// that took ages to process
 #ifndef FD_SETSIZE
-#define FD_SETSIZE 4096
+#define FD_SETSIZE 96
 #endif
 
 #include <io.h>