update miri

Author: RalfJung

Cargo.lock

@@ -1613,7 +1613,9 @@ dependencies = [
  "compiletest_rs 0.3.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "directories 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hex 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-workspace-hack 1.0.0",
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "shell-escape 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",