ndk_sync_codec_fuzzer : Resolved Direct Memory Leak Issue

mFormat in NdkMediaCodecFuzzerBase class wasn't freed in
some cases. This CL creates a destructor for NdkMediaCodecFuzzerBase
and adds a free for mFormat in destructor. Also removes local call
to AMediaFormat_delete in ndk_sync_codec_fuzzer.

Test: $ANDROID_HOST_OUT/fuzz/x86_64/ndk_sync_codec_fuzzer/ndk_sync_codec_fuzzer CORPUS_DIR
Bug: 243215191

Change-Id: I84608dc934b21b71769a7d798af3f9bbf476d37e
(cherry picked from commit 03e1c251d2e090402a2bad30e8bee8924e065622)