ossfuzz.sh: use CXX for compiling libldac_encoder_fuzzer.cc am: ff6a91f6a8 am: d4a121864c am: 4fdacc2b91 am: 17947422cc

Original change: https://android-review.googlesource.com/c/platform/external/libldac/+/2687830

Change-Id: I1f04871e36570334b0871d0c938b6d21ce3f8749
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>