Backport fixes for sharing wrappers when type attributes are involved (#21537)
* [wasm] Fix the handling of i8/u8 in get_wrapper_shared_type_full (). (#19859)
Previously, these were returned verbatim, which caused sharing issues when the type had
attributes.
Fixes https://github.com/mono/mono/issues/19841.
* [aot] Fix the handling of r4/r8 parameter types with attributes during generic sharing. (#20217)
The attributes need to be ignored as with the other types, otherwise gsharedvt wrappers for signatures with
parameters like double f = default will not be found.
Fixes https://github.com/mono/mono/issues/20195.
Co-authored-by: Zoltan Varga <vargaz@gmail.com>