Use "resilient conformance" logic for deciding protocol dependencies involving Sendable
When compiling with library evolution and a pre-Swift 6.0 deployment
target, a mismatch between the notion of resilience used for determining
whether a protocol that inherits Sendable might need to be treated as
"dependent" differed from how other parts of IR generation decided
whether to conformance should be considered as resilient. The
difference came when both the protocol and its conforming type are in
the same module as the user.
Switch over to the "is this conformance resilient?" query that takes
into account such conformances.
Fixes rdar://136586922.