Delete unused fds in sceNetEpollDestroy and sys_socketclose (#3976)

This issue would cause memory leaks in some EA titles, also just generally makes it harder to debug stuff when the fd table is flooded with closed sockets and epolls.

src/core/libraries/network/net.cpp

@@ -803,6 +803,7 @@ int PS4_SYSV_ABI sceNetEpollDestroy(OrbisNetId epollid) {
     LOG_DEBUG(Lib_Net, "called, epollid = {} ({})", epollid, file->epoll->name);
 
     file->epoll->Destroy();
+    FDTable::Instance()->DeleteHandle(epollid);
 
     return ORBIS_OK;
 }

src/core/libraries/network/sys_net.cpp

@@ -335,6 +335,7 @@ int PS4_SYSV_ABI sys_socketclose(OrbisNetId s) {
     LOG_DEBUG(Lib_Net, "s = {} ({})", s, file->m_guest_name);
     int returncode = file->socket->Close();
     if (returncode >= 0) {
+        FDTable::Instance()->DeleteHandle(s);
         return returncode;
     }
     LOG_ERROR(Lib_Net, "error code returned: {}", (u32)*Libraries::Kernel::__Error());