vm capi: more MRI C API enum types compatibility.

* add RUBY_ prefix for T_XXX types
* add backward compatibility for MRI's enum types.

Currently, MRI provides `RUBY_T_XXX` forms of enum types in C extension.
But, Rubinius does not provide these of enum types.
So, it causes gem installation error, when gem uses `RUBY_T_XXX` in C extension.

e.g. glib2 gem:

```log
rbglib_utils.c: In function 'rg_s_parse_debug_string':
rbglib_utils.c:250:22: error: 'RUBY_T_HASH' undeclared (first use in this function)
     Check_Type(keys, RUBY_T_HASH);
```