Only destroy the block if it hasn't been pushed into the block stack, or it will be destroyed again when destroying the block stack.
The entry and exit basic blocks might be destroyed before they are created. Found by instrument test. Add checks to fix the issue.
Add fast jit fixed virtual register import_func_ptrs_reg and func_type_indexes_reg for the preparation of further optimizations.
Import WAMR Fast JIT which is a lightweight JIT with quick startup, small footprint, relatively good performance (~40% to ~50% of LLVM JIT) and good portability. Platforms supported: Linux, MacOS and Linux SGX. Arch supported: x86-64.
