implement stringref based on libdyntype

[xujuntwt95329]

To use stringref feature:

1. clone WAMR stringref branch

   cd runtime-library/deps
   # backup original WAMR folder if exists
   git clone --branch stringref_dev https://github.com/yviansu/wasm-micro-runtime.git wamr-gc

2. build iwasm_gc with stringref feature

   cd runtime-library
   mkdir build && cd build
   cmake .. -DWAMR_BUILD_STRINGREF=1
   make

3. build app with stringref feature

   node cli/ts2wasm.js test.ts --enableStringRef  -o test.wasm