fix(ext/ffi): improve error messages in FFI module (#17786)

Fixes denoland#16922.

The error messages in the `ffi` module are somewhat cryptic when passing
functions that have invalid `parameters` or `result` type strings. While
the generated serializer for the `ForeignFunction` struct correctly
outputs a correct and verbose message, the user sees a far less helpful
`data did not match any variant` message instead.

The underlying cause appears to be the fallback message in the
auto-derived deserializer for untagged enums [1] generated as a result
of `ForeignSymbol` being marked as `#[serde(untagged)]` [2]. Passing an
unexpected value for `NativeType` causes it to error out while
attempting to deserialize both enum variants -- once because it's not a
match for the `ForeignStatic` variant, and once because the
`ForeignFunction` deserializer rejects the invalid type for the
parameters/return type. This is currently open as [serde
#773](https://github.com/serde-rs/serde/issues/773), and not a trivial
exercise to fix generically.

[1]
https://github.com/serde-rs/serde/blob/v0.9.7/serde_derive/src/de.rs#L730
[2] https://github.com/denoland/deno/blob/main/ext/ffi/dlfcn.rs#L102
[3] https://github.com/serde-rs/serde/issues/773

Note that the auto-generated deserializer for untagged enums uses a
private API to buffer deserializer content that we don't have access to.
Instead, we can make use of the `serde_value` crate to buffer the
values. This can likely be removed once the official buffering API lands
(see [4] and [5]). In addition, this crate pulls in `serde_json` as a
cheap way to test that the deserializer works properly.

[4] https://github.com/serde-rs/serde/issues/741
[5] https://github.com/serde-rs/serde/pull/2348

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