swift

641cfe06 - [Concurrency] Fix `@Sendable` closures not inferring `nonisolated(nonsending)`

[Concurrency] Fix `@Sendable` closures not inferring `nonisolated(nonsending)` If there are no explicit concurrency attributes, isolated parameters, or captures associated with the closure it should infer `nonisolated(nonsending)` for the parent conversion injected by the solver (this conversion is injected because the solver cannot check captures to elide it). The change pushes `isIsolationInferenceBoundaryClosure` check down with added benefit of getting preconcurrency context from the parent. (cherry picked from commit 3ae34e8e68ce3f105a067451b7df092324e24d34)