test: Add default term width to tests

Author: Muscraft

crates/cargo-test-support/src/lib.rs

@@ -1423,6 +1423,7 @@ pub trait TestEnvCommandExt: Sized {
             .env("__CARGO_TEST_DISABLE_GLOBAL_KNOWN_HOST", "1")
             // Set retry sleep to 1 millisecond.
             .env("__CARGO_TEST_FIXED_RETRY_SLEEP_MS", "1")
+            .env("__CARGO_TEST_TTY_WIDTH_DO_NOT_USE_THIS", "140")
             // Incremental generates a huge amount of data per test, which we
             // don't particularly need. Tests that specifically need to check
             // the incremental behavior should turn this back on.