Auto merge of #5864 - rust-lang:ci_debug, r=Manishearth
Auto merge of #5864 - rust-lang:ci_debug, r=Manishearth

Fix ui-cargo tests in CI

r? @ebroto

The `ui-toml` tests set the `CARGO_MANIFEST_DIR` var, but never reset it, so the `ui-cargo` tests used it also and then found a faulty `clippy.toml` file

changelog: none

aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust