Disable cargo tests for now
Disable cargo tests for now

These depend on rustc being bug-free and it looks like that's not
currently entirely the case (e.g., we know of at least one bug that
introduces nondeterminism).

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