Fixed file descriptor leak in IMemory

Include dup in critical section to avoid multiple dup calls from
different threads.
The leak happens more frequently since patch in frameworks/av -
6773d4777f4ccbbe6377e4ae1b42c117066ae6ba when recording video since it
will access IMemory from CameraUtils::isNativeHandleMetadata

Bug: 28924660
Author: Henrik Antonsson <henrik.antonsson@sonymobile.com>
Change-Id: I769a914c3adc505b522659a0c43719fb2922e6fd