Automatically try applying non-MachineApplicable suggestions

[estebank]

In the same spirit as the following environment variable https://github.com/rust-lang/cargo/blob/dc83ead224d8622f748f507574e1448a28d8dcc7/src/cargo/ops/fix.rs#L419

cargo fix could try first applying all suggestions and if it fails applying only the MachineApplicable ones. This could be problematic depending on the codebase size due to compilation times, but may be it could be worked around by keeping rustc statistics of prior runs and only do this if compile times are short "enough".