Blocked `MutatingUseContext::Projection` for all locals of kind `LocalKind::Temp`. Added a cache of `LocalKind`s to `CanConstProp`
Blocked `MutatingUseContext::Projection` for all locals of kind `LocalKind::Temp`. Added a cache of `LocalKind`s to `CanConstProp`

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