cargo saw-build/saw-rustc: Don't generate crux-mir-related test script

[RyanGlScott]

Currently, if you compile code with the cargo saw-build or saw-rustc commands, then it will generate a test script with the following contents:

#!/bin/sh
exec "${CRUX_MIR:-crux-mir}" --assert-false-on-error --cargo-test-file "$(dirname "$0")"/'$CRATE_NAME.linked-mir.json' "$@"

This is silly to do in the context of cargo saw-build/saw-rustc, however, as these commands aren't meant to be used in conjunction with crux-mir. We should suppress generating this script when using these commands.

[spernsteiner]

Does saw-rustc always emit this, or only when run with saw-rustc --test? My vague recollection of the way it was supposed to work for crux was that cargo crux-test runs RUSTC_WRAPPER=... cargo test, and the final build step invokes rustc (actually mir-json) with the --test flag, which causes mir-json to emit the test script. So I would expect saw-rustc to emit the script only when passed --test.

As for cargo saw-build, if it's currently using cargo test (like cargo crux-test does), it might be better to switch it to cargo build.

[RyanGlScott]

saw-rustc always emits this, as saw-rustc always passes --test to the underlying rustc invocation. In fact, if you try to run saw-rustc --test, it fails:

$ SAW_RUST_LIBRARY_PATH=$(pwd)/../../Haskell/crucible/crux-mir/rlibs saw-rustc --test hello_world.rs
test build - extract output path - ["rustc", "--test", "hello_world.rs", "--test", "--target", "x86_64-unknown-linux-gnu", "--cfg", "crux", "-L", "/home/ryanscott/Documents/Hacking/Rust/hello-world/../../Haskell/crucible/crux-mir/rlibs", "--sysroot", "/home/ryanscott/Documents/Hacking/Rust/hello-world/../../Haskell/crucible/crux-mir/rlibs"]
error: Option 'test' given more than once

And indeed, cargo saw-build uses cargo test currently, just like cargo crux-test.