The `-experimental-lazy-typecheck` and `-experimental-skip-non-exportable-decls`
flags are not safe to use when emitting a non-resilient module because the
clients of non-resilient modules expect to have access to all the members of a
type in order to e.g. compute the size the type. The
`-experimental-skip-non-exportable-decls` flag skips serialization of
non-public members and would therefore cause mis-compilation. The
`-experimental-lazy-typecheck` is theoretically safe for non-resilient modules
but more requestification work is needed before it can be used successfully.
Resolves rdar://122272758
Instances of `MacroExpansionDecl` may be found in the AST when declarations are
expanded from freestanding declaration macros and therefore exportability
computations must be prepared to handle them.
Resolves rdar://119449439
