This commit removes "Deno.core" namespace. It is strictly private API
that has no stability guarantees, we were supposed to remove it long time ago.
Co-authored-by: Yoshiya Hinosawa <stibium121@gmail.com>
Makes `op_ffi_ptr_of` fast. One of the tests changed from printing
`false` to `true` as the fast `&[u8]` slice path creates the slice with
a null pointer. Thus the `op_ffi_ptr_of` will now return a null pointer
value whereas previously it returned a dangling pointer value.
This PR makes pointer read methods of `Deno.UnsafePointerView` Fast API
compliant, with the exception of `getCString` which cannot be made fast
with current V8 Fast API.
