Fix errors in CI.

[jdm]

From the lint job:

 error: methods `get_bool` and `get_list` are never used
   --> rcdom/tests/xml-tokenizer.rs:147:8
    |
143 | trait JsonExt: Sized {
    |       ------- methods in this trait
...
147 |     fn get_bool(&self) -> bool;
    |        ^^^^^^^^
148 |     fn get_obj(&self) -> &Map<String, Self>;
149 |     fn get_list(&self) -> &Vec<Self>;
    |        ^^^^^^^^
    |
    = note: `-D dead-code` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(dead_code)]`

From the nightly CI:

error: unexpected `cfg` condition name: `trace_tokenizer`
   --> html5ever/src/tokenizer/mod.rs:625:11
    |
625 | #[cfg(not(trace_tokenizer))]
    |
    = help: consider using a Cargo feature instead
    = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
             [lints.rust]
             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(trace_tokenizer)'] }
    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(trace_tokenizer)");` to the top of the `build.rs`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration