The wasm loader is failing when multi-module support is on and the dependent
modules are not found; this enforces the AOT compiler integrations to prepare
dependent modules while it isn't necessary.
This PR allows allows missing imports in wasm loader and report error in wasm
instantiation instead, which enables the integrated AOT compiler to work as if
the multi-module support isn't turned on.
Fix#3545 and update the build configuration for multi-module sample:
- pass debug to AOT-compiled modules
- support optional DUMP_CALL_STACK
- support optional GC
- Add declarations related to emitting AOT files into a separate header file
named `aot_emit_aot_file.h`
- Add API `aot_emit_aot_file_buf_ex` and refactor `aot_emit_aot_file_buf` to call it
- Expose some APIs in aot_export.h
