Typechecking of dict, set, and list literals currentlly
goes through typechecking of the generic dict/set/list
constructor internally. This is usually fine but becomes
horrendously slow when the number of items is large:
 - for generic methods, `infer_arg_types_in_context` is
   called twice
 - `infer_arg_types_in_context` is O(n**2) where `n` is
   the number of arguments, which, in the case of a
   literal, is the number of items.

Add an `O(n)` fast path for deriving the type of simple
container literal expressions. This fast path only handle
a subset of cases but it provides a tremendous speedup for
the relatively common case of large literal constants.

The real-world example that motivated this change is a
1889 lines long dict constant representing the parsed value
of a mock JSON response from a 3rd party service, where
typechecking previously took upwards of 50s and is now
down to under 1s with this fast path.