Testing Heph using Miri

[Thomasdezeeuw]

Currently fails with

error: unsupported operation: `open` not available when isolation is enabled
    --> /home/runner/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/pal/unix/fs.rs:1185:36
     |
1185 |         let fd = cvt_r(|| unsafe { open64(path.as_ptr(), flags, opts.mode as c_int) })?;
     |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `open` not available when isolation is enabled
     |
     = help: set `MIRIFLAGS=-Zmiri-disable-isolation` to disable isolation;
     = help: or set `MIRIFLAGS=-Zmiri-isolation-error=warn` to make Miri return an error code from isolated operations (if supported for that operation) and continue with a warning
     = note: BACKTRACE on thread `test_1_hello_wo`:
     = note: inside closure at /home/runner/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/pal/unix/fs.rs:1185:36: 1185:84
     = note: inside `std::sys::pal::unix::cvt_r::<i32, {closure@std::sys::pal::unix::fs::File::open_c::{closure#0}}>` at /home/runner/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/pal/unix/mod.rs:325:19: 325:22
     = note: inside `std::sys::pal::unix::fs::File::open_c` at /home/runner/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/pal/unix/fs.rs:1185:18: 1185:87
     = note: inside `std::sys::pal::unix::process::process_common::Stdio::to_child_stdio` at /home/runner/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/pal/unix/process/process_common.rs:481:26: 481:55
     = note: inside `std::sys::pal::unix::process::process_common::Command::setup_io` at /home/runner/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/pal/unix/process/process_common.rs:384:40: 384:66
     = note: inside `std::sys::pal::unix::process::process_inner::<impl std::sys::pal::unix::process::process_common::Command>::spawn` at /home/runner/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/pal/unix/process/process_unix.rs:70:30: 70:65
     = note: inside `std::process::Command::spawn` at /home/runner/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/process.rs:1037:9: 1037:52
note: inside `run_example`
    --> tests/examples.rs:124:23
     |
124  |               let res = Command::new(path)
     |  _______________________^
125  | |                 .stdin(Stdio::null())
126  | |                 .stderr(Stdio::piped())
127  | |                 .stdout(Stdio::piped())
128  | |                 .spawn()
     | |________________________^
note: inside `run_example_output`
    --> tests/examples.rs:103:17
     |
103  |     let child = run_example(name);
     |                 ^^^^^^^^^^^^^^^^^
note: inside `test_1_hello_world`
    --> tests/examples.rs:11:18
     |
11   |     let output = run_example_output("1_hello_world");
     |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: inside closure
    --> tests/examples.rs:10:24
     |
9    | #[test]
     | ------- in this procedural macro expansion
10   | fn test_1_hello_world() {
     |                        ^
     = note: this error originates in the attribute macro `test` (in Nightly builds, run with -Z macro-backtrace for more info)

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

error: aborting due to 1 previous error

error: test failed, to rerun pass `--test examples`