Revert "Explicitly add visionOS availability to tests that check availability. (#424)" (#426)

This reverts commit 406564e.

The revert is needed because Swift 5.10 does not recognize visionOS and
swift-testing does not currently have the ability to conditionalize
availability with `#if compiler(>=5.11)`.

We can reapply the change in the future if/when we require Swift 6.

### Checklist:

- [x] Code and documentation should follow the style of the [Style
Guide](https://github.com/apple/swift-testing/blob/main/Documentation/StyleGuide.md).
- [x] If public symbols are renamed or modified, DocC references should
be updated.

Author: grynspan

Tests/TestingTests/EventRecorderTests.swift

@@ -403,11 +403,11 @@ struct EventRecorderTests {
   func unavailablePigeon() {}
 
   @Test("Future Grouse", .hidden)
-  @available(macOS 999.0, iOS 999.0, watchOS 999.0, tvOS 999.0, visionOS 999.0, *)
+  @available(macOS 999.0, iOS 999.0, watchOS 999.0, tvOS 999.0, *)
   func futureGrouse() {}
 
   @Test("Future Goose", .hidden)
-  @available(macOS 999, iOS 999, watchOS 999, tvOS 999, visionOS 999.0, *)
+  @available(macOS 999, iOS 999, watchOS 999, tvOS 999, *)
   func futureGoose() {}
 
   @Test("Future Mouse", .hidden)

Tests/TestingTests/RunnerTests.swift

@@ -615,21 +615,20 @@ final class RunnerTests: XCTestCase {
 
 #if SWT_TARGET_OS_APPLE
     @Test(.hidden)
-    @available(macOS 999.0, iOS 999.0, watchOS 999.0, tvOS 999.0, visionOS 999.0, *)
+    @available(macOS 999.0, iOS 999.0, watchOS 999.0, tvOS 999.0, *)
     func futureAvailable() {}
 
     @Test(.hidden)
     @available(macOS, introduced: 999.0)
     @available(iOS, introduced: 999.0)
     @available(watchOS, introduced: 999.0)
     @available(tvOS, introduced: 999.0)
-    @available(visionOS, introduced: 999.0)
     func futureAvailableLongForm() {}
 
     @Suite(.hidden)
     struct U {
       @Test(.hidden)
-      @available(macOS 999.0, iOS 999.0, watchOS 999.0, tvOS 999.0, visionOS 999.0, *)
+      @available(macOS 999.0, iOS 999.0, watchOS 999.0, tvOS 999.0, *)
       func f() {}
 
       @Test(.hidden)
@@ -644,7 +643,6 @@ final class RunnerTests: XCTestCase {
       @available(iOS, introduced: 999.0)
       @available(watchOS, introduced: 999.0)
       @available(tvOS, introduced: 999.0)
-      @available(visionOS, introduced: 999.0)
       func f() {}
     }
 #endif
@@ -679,7 +677,6 @@ final class RunnerTests: XCTestCase {
     @available(iOS, introduced: 1.0, obsoleted: 999.0)
     @available(watchOS, introduced: 1.0, obsoleted: 999.0)
     @available(tvOS, introduced: 1.0, obsoleted: 999.0)
-    @available(visionOS, introduced: 1.0, obsoleted: 999.0)
     func obsoleted() {}
   }
 
@@ -705,7 +702,6 @@ final class RunnerTests: XCTestCase {
     @available(iOS, introduced: 999.0, message: "Expected Message")
     @available(watchOS, introduced: 999.0, message: "Expected Message")
     @available(tvOS, introduced: 999.0, message: "Expected Message")
-    @available(visionOS, introduced: 999.0, message: "Expected Message")
     func futureAvailableLongForm() {}
 #endif
   }
@@ -843,15 +839,13 @@ final class RunnerTests: XCTestCase {
     @available(iOS, deprecated: 1.0)
     @available(watchOS, deprecated: 1.0)
     @available(tvOS, deprecated: 1.0)
-    @available(visionOS, deprecated: 1.0)
     func deprecatedAppleCallee() {}
 
     @Test(.hidden)
     @available(macOS, deprecated: 1.0)
     @available(iOS, deprecated: 1.0)
     @available(watchOS, deprecated: 1.0)
     @available(tvOS, deprecated: 1.0)
-    @available(visionOS, deprecated: 1.0)
     func deprecatedApple() {
       deprecatedAppleCallee()
     }