Don't run jit tests on macOS
Don't run jit tests on macOS

Workaround for #671

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