swift234

[lower-aggregate-instrs] Add an additional type lowering style "DeepNoEnum" for use in lowering aggregate memory operations.

The idea here is that the aggregate memory operation is lowered deep recursively
for all types except enums which recieve a shallow lowering. This prevents code
bloat due to the deep lowering of an enum requiring the creation of a bunch of
new basic blocks, code bloat which we do not want.

Another thing to note is that this method is actually not used anywhere else
currently, but in case this behavior was left in on purpose I decided to extend
it by adding the enum class flag rather than just changing the underlying
behavior (i.e. making deep not lower enum values).

Swift SVN r11748