Unset RUST_NEW_ERROR_FORMAT in compiletest.
Unset RUST_NEW_ERROR_FORMAT in compiletest.

aidancully/rust,graydon/rust,rust-lang/miri,aidancully/rust,GBGamer/rust,GBGamer/rust,rust-lang/miri,graydon/rust,tsion/miri,GBGamer/rust,graydon/rust,aidancully/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,rust-lang/miri,graydon/rust,rust-lang/miri,aidancully/rust,graydon/rust,GBGamer/rust,graydon/rust