Check: Revert "Sema: Don't diagnose declarations more available than unavailable container."

[ktoso]

Check if #64515 is what caused the issues mentioned below in #64517

I'm concurrently investigating if any of my executor PRs could have caused this.

/Users/ec2-user/jenkins/workspace/swift-PR-macos/branch-main/swift/test/ModuleInterface/actor_availability.swift:95:15: warning: symbols that are @_spi_available on all platforms should use @_spi instead
public struct SPIAvailableStruct {
              ^
/Users/ec2-user/jenkins/workspace/swift-PR-macos/branch-main/build/buildbot_incremental/swift-macosx-x86_64/test-iphonesimulator-x86_64/ModuleInterface/Output/actor_availability.swift.tmp/Library.swiftinterface:79:16: error: type 'SPIAvailableStruct.UnavailableNestedActor' does not conform to protocol 'Actor'
  public actor UnavailableNestedActor {
               ^
/Users/ec2-user/jenkins/workspace/swift-PR-macos/branch-main/build/buildbot_incremental/swift-macosx-x86_64/test-iphonesimulator-x86_64/ModuleInterface/Output/actor_availability.swift.tmp/Library.swiftinterface:85:62: error: unavailable property 'unownedExecutor' was used to satisfy a requirement of protocol 'Actor'
    @_semantics("defaultActor") nonisolated final public var unownedExecutor: _Concurrency.UnownedSerialExecutor {
                                                             ^
_Concurrency.Actor:3:21: note: requirement 'unownedExecutor' declared here
    nonisolated var unownedExecutor: UnownedSerialExecutor { get }
                    ^
/Users/ec2-user/jenkins/workspace/swift-PR-macos/branch-main/build/buildbot_incremental/swift-macosx-x86_64/test-iphonesimulator-x86_64/ModuleInterface/Output/actor_availability.swift.tmp/Library.swiftinterface:1:1: error: failed to verify module interface of 'Library' due to the errors above; the textual interface may be broken by project issues or a compiler bug
// swift-interface-format-version: 1.0
^

This reverts commit 620462d.

[ktoso]

@swift-ci please test macOS

[ktoso]

The Job not found issue; I'm still trying to figure it out -- going to PR a workaround for the tests...

@swift-ci please clean test macOS

[tshortli]

Could you mark the test as unsupported on the platforms where it's failing, rather than reverting the whole change? I'll follow up to fix the test.

[ktoso]

Okey I'll do that instead -- primarily wanted to see here if this was the change that caused the issues.
Folks assume it's my fault whenever anything 'executor' shows up in logs 🥲

I'll change this to disable the test and merge to give you time to follow up