[SR-8252] Consolidate and Fix -debug-crash-* Flags

[CodaFi]

Previous ID	SR-8252
Radar	None
Original Reporter	@CodaFi
Type	Improvement

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Improvement, StarterBug
Assignee	None
Priority	Medium

md5: 85fb82c2ea0303f5308473609b79bde5

Issue Description:

Currently, Swift has -debug-crash-immediately and -debug-crash-after-parse and -debug-assert-after-parse. The problem is twofold:

1) -debug-assert-after-parse understands the old hat meaning of "-parse" which used to mean "parse and type check". Now that the compiler understands these are distinct actions, this flag is misnamed.

2) The more useful distinction is crashing immediately versus crashing after a particular phase.

We should generalize -debug-assert and -debug-crash to mean "assert after the current frontend action finishes" or "crash after the current frontend action finishes" respectively. -debug-crash-immediately should still be retained because there needs to be a way to crash argument parsing.

[CodaFi]

@belkadan Do you think this would make a good starter bug?

[belkadan]

Sure, that makes sense. Good to have a pool of those available.