Add more types for attr_container, e.g. uint8, uint32, uint64
Add more APIs for attr_container for int8, int16 and int32 types
Rename fields of the union 'jvalue' and refactor some files that use attr_container
Update wasm app build scripts for wasi-sdk-12.0: add --export=__main_argc_argv, remove --no-threads
Lookup function with name "__main_argc_argv" as main function besides "main"
Change module_malloc to runtime_malloc in wasi native lib
Refine classic interpreter op_block and op_br_table
Refine faster interpreter op_br_table
Signed-off-by: Wenyong Huang <wenyong.huang@intel.com>