[Feature Request] revert move AccountDataCache

[nkysg]

Feature Request

Describe the Feature Request

Because of this feature starcoinorg/diem#161
we changed

pub struct AccountDataCache {
    data_map: BTreeMap<StructTag, (MoveTypeLayout, GlobalValue)>,
    module_map: BTreeMap<Identifier, Vec<u8>>,
}

we need to revert to this one

pub struct AccountDataCache {
    data_map: BTreeMap<Type, (MoveTypeLayout, GlobalValue)>,
    module_map: BTreeMap<Identifier, Vec<u8>>,
}

Describe Preferred Solution

Describe Alternatives

Related Code

Additional Context

If the feature request is approved, would you be willing to submit a PR?
Yes / No (Help can be provided if you need assistance submitting a PR)