Fix benchmark crash on wait for destroyed callback

Fix benchmark crash error:

`FORTIFY: pthread_mutex_lock called on a destroyed mutex`

Caused by the bench loop trying to wait on the callback promise future
after the callback instance was destroyed.

The fix grabs the promise future before performing the HAL operation, so
it can access the fulfilled value after the promise fulfilled and then
destroyed.

Change-Id: I4504129672a11ad1662ea36c79f522d754535765
Fix: 336977792
Test: atest VibratorHalIntegrationBenchmark
Flag: TEST_ONLY