Use RUSTFLAGS to set the optimization level (#10719)

* Use RUSTFLAGS to set the optimization level

Cargo has a [quirk]() in how configuration settings are propagated when `cargo test` runs: local code respect the settings in `[profile.test]` but all dependencies use the `[profile.dev]` settings. Here we force `opt-level=3` for all dependencies.

* Remove unused profile settings

* Maybe like this?

* Turn off incremental compilation

* Remove colors; try again with overflow-checks on

* Use quiet CI machine

* Turn overflow checking back on

* Be explicit about what options we use

* Remove "quiet machine" override

Cargo.toml

@@ -117,10 +117,9 @@ path = "parity/lib.rs"
 path = "parity/main.rs"
 name = "parity"
 
-[profile.dev]
-
 [profile.release]
 debug = false
+lto = true
 
 [workspace]
 # This should only list projects that are not

scripts/gitlab/test-linux.sh

@@ -14,4 +14,5 @@ rustup default $1
 rustup show
 
 echo "________Running Parity Full Test Suite________"
-time cargo test $OPTIONS --features "$FEATURES" --locked --all --target $CARGO_TARGET --verbose --color=always -- --test-threads $THREADS
+# Why are we using RUSTFLAGS? See https://github.com/paritytech/parity-ethereum/pull/10719
+CARGO_INCREMENTAL=0 RUSTFLAGS="-C opt-level=3 -C overflow-checks=on -C debuginfo=2" time cargo test $OPTIONS --features "$FEATURES" --locked --all --target $CARGO_TARGET --verbose --color=never -- --test-threads $THREADS