[projection] Introduce two new types NewProjection and NewProjectionPath.

NewProjection is a re-architecting of Projection that supports all of
the same functionality as Projection but in 1/3 of the original size (in
the common case). It is able to accomplish this by removing the base
type out of NewProjection itself and into users such as
NewProjectionPath. Thus NewProjection is now strictly an index from some
parent type rather than being a parent type and an index.

NewProjectionPath also has all of the same functionality as
ProjectionPath, but due to NewProjection being smaller than Projection
is smaller than ProjectionPath.

Used together NewProjection/NewProjectionPath yields the same output as
Projection/ProjectionPath when evaluating the LSLocation dumping tests.

Additionally, NewProjection is more flexible than Projection and will
for free give us the ability to perform AA on index_addr/index_raw_addr
as well as be able to integrate casts into the projection paradigm.

rdar://22484381

Author: gottesmm