[SR-14901] Code completion taking very long (~4 minutes) because of chained `==` operators in invalid expression

[ahoppen]

Previous ID	SR-14901
Radar	rdar://77257754
Original Reporter	@ahoppen
Type	Bug

Additional Detail from JIRA

Votes	0
Component/s	CodeCompletion
Labels	Bug, FoundByStressTester
Assignee	None
Priority	Medium

md5: 6f3c99d791a2b9f50df30b3cd5bbcc5f

Issue Description:

The following test case takes ~4 minutes to complete

// RUN: %swift-ide-test --code-completion --source-filename %s --code-completion-token COMPLETE

b == b.#^COMPLETE^# == b == b

Looking at -debug-constraints this appears to be because the type checker needs to check all combinations of the == overload.