server: Don't set the idle event when a queue is destroyed, instead return success in WaitForInputIdle on process exit.

The issue was detected with Valgrind.

Found by Valgrind.

Found by Valgrind.

Found by Valgrind.

Found by Valgrind.

Now we only allocate enough memory to exactly match the size of the
constructed string. Before, we were leaving some memory uninitialized
and overwriting the allocated memory in certain circum.