Support VNDK ABI dump in JSON format

header-abi-dumper outputs JSON files if -text-format=Json is specified.
It uses libjsoncpp to convert IR to JSON. The output files follow the
schema of the protobuf, but the default values, such as empty array,
false and 0, are not omitted.

Bug: 112877706
Test: ./create_reference_dumps.py -libs libstagefright_bufferqueue_helper -products aosp_arm64
Change-Id: I0f964ee0530c444035170f451217bb005ee6107b