Removed all usages of lazy_static and replaced them with once_cell

[Kixiron]

• Replaced lazy_static with once_cell (using the parking_lot feature for smaller, faster and non-poisoning locks)
• Tweaked load_rustc_resource_suffix, it now substitutes a dummy rustc version for tests when one isn't found. This fixed a lot of intermittent (and essentially false) test failures for me, I can remove it if it's uneeded

[pietroalbini]

This fixed a lot of intermittent (and essentially false) test failures for me, I can remove it if it's uneeded

Those are not test failures: when that function fails the error message is logged with log::error!(), and the execution proceeds as normal. If you disable output capturing you'll see that message in every test using the frontend. It's just that the test is having another error, so you also see the log.

[Kixiron]

It was causing a lot of errors for me (as opposed to being silent), 29 of them to be exact. Without the patch I made I get lots of this, whereas after all tests pass

---- web::rustdoc::test::test_no_trailing_slash stdout ----
[2020-06-29T19:14:51Z ERROR cratesfyi::web::page::templates] Failed to load rustc resource suffix: ErrorMessage { msg: "missing rustc version" }
thread 'web::rustdoc::test::test_no_trailing_slash' panicked at '/crate/dummy/0.1.0/target-redirect/x86_64-apple-darwin: expected redirect to /dummy/0.1.0/dummy/, got 500 Internal Server Error', src\test\mod.rs:79:13

---- web::source::tests::cargo_ok_not_skipped stdout ----
[2020-06-29T19:14:51Z ERROR cratesfyi::web::page::templates] Failed to load rustc resource suffix: ErrorMessage { msg: "missing rustc version" }
thread 'web::source::tests::cargo_ok_not_skipped' panicked at 'failed to GET /crate/fake/0.1.0/source/: 500 Internal Server Error', src\test\mod.rs:44:5

---- web::rustdoc::test::yanked_release_shows_warning_in_nav stdout ----
[2020-06-29T19:14:51Z ERROR cratesfyi::web::page::templates] Failed to load rustc resource suffix: ErrorMessage { msg: "missing rustc version" }
thread 'web::rustdoc::test::yanked_release_shows_warning_in_nav' panicked at 'failed to GET /dummy/0.1.0/dummy/: 500 Internal Server Error', src\test\mod.rs:44:5

---- web::test::test_index_returns_success stdout ----
[2020-06-29T19:14:55Z ERROR cratesfyi::web::page::templates] Failed to load rustc resource suffix: ErrorMessage { msg: "missing rustc version" }
thread 'web::test::test_index_returns_success' panicked at 'assertion failed: web.get("/").send()?.status().is_success()', src\web\mod.rs:637:13

---- web::test::test_show_clipboard_for_crate_pages stdout ----
[2020-06-29T19:14:55Z ERROR cratesfyi::web::page::templates] Failed to load rustc resource suffix: ErrorMessage { msg: "missing rustc version" }
thread 'web::test::test_show_clipboard_for_crate_pages' panicked at 'assertion failed: clipboard_is_present_for_path("/crate/fake_crate/0.0.1", web)', src\web\mod.rs:653:13

[Kixiron]

And the docker failure here is due to #864, it's fixed in #849

[pietroalbini]

@Kixiron hmm? The tests you mention correctly pass for me on master.

[pietroalbini]

Those tests also work on this PR with the #[cfg(test)] removed.

[Kixiron]

I removed the cfg