single defining has same behavior

global

1. see vm/vm_options.rs for usage and default values
2. added mu_fastimpl_new_with_opts under vm/api/api_impl/muvm.rs

going to test it with test_jit suite

now

also fixed a bug related with exception block label

NOTE: Only fixed hand-written ASMs. Emitted ".s" files still have problems.

internal id and machine id do not persist during serialization
and restoration. Currently I use fixed ID for machine registers.
But internal id is still generated, this might be a problem in
the future.

(for blocks created during instruction selection)

gonna implement THREADEXIT

FIXME: GC settings such as heap size, n_gcthreads, should be properly serialized

gonna port tests to this repo