Some optimization passes _improve_ compile times [1]. So we want to run
some passes even with `-Copt-level=0`. That means that some of the lines
in the test can be optimized away. To make regression testing more
robust, we also want to run the test with such passes disabled. The
solution is to use two revisions. One with default `-Copt-level=0`
passes, and one "even less optimized", with enough optimization passes
disabled to keep the maximum number of lines steppable.
[1]: https://github.com/rust-lang/compiler-team/issues/319
We only run LLDB 1500 in CI. Any test with a min-lldb-version above that
is currently ignored. It's not clear any of these tests actually work
with that LLDB version, and they definitely don't work on LLDB ~2100.
So, ignore them until we fix debuginfo testing.
So that when we later add support for revisions we can use the same
syntax for revisions as elsewhere.
This also prevents people from making typos for commands since
`src/tools/compiletest/src/directives/directive_names.rs` will catch such
typos now.
Note that we one FIXME for a non-trivial change for later:
```
// FIXME(148097): Change `// cdb-checksimple_closure` to `//@ cdb-check:simple_closure`
```
Martin Nordholts