swift234

Split getAccessibility() into getFormalAccess() and getEffectiveAccess().

Currently a no-op, but effective access for entities within the current
module will soon need to take testability into account. This declaration:

  internal func foo() {}

has a formal access of 'internal', but an effective access of 'public' if
we're in a testable mode.

Part of rdar://problem/17732115 (testability)

Swift SVN r26472