ossfuzz.sh: use CXX for compiling libldac_encoder_fuzzer.cc am: ff6a91f6a8 am: d4a121864c am: 4fdacc2b91 am: 17947422cc am: 1b30cd21c7

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

Change-Id: I14ff6dca2c9dc5c4ff5149efca638fdada745440
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>