swift234

Use the 'self consumed' analysis to eliminate releases of consumed self

Previously, SILGen would store a null pointer into the self box upon
encountering a constructor delegation that consumes self. This was a
constant source of bugs. Now, use the new analysis to make this use
DI information instead, emitting an extra bit at runtime if necessary.

Also re-organize the DI tests for initializers, and add CHECK: lines
instead of just asserting we don't crash or diagnose.

Swift SVN r32604