[Tests] NFC: Add iOS requirement to selectConfiguredTargets instead of artifacts

The test checks whether it's possible to select an appropriate target given a run
destination and uses both macOS and iOS SDKs.

If there is no iOS SDK installed it won't be possible to configure a test target
for that platform and the test is going to fail.

Resolves: rdar://162067445

Author: xedin

Tests/SwiftBuildTests/InspectBuildDescriptionTests.swift

@@ -74,7 +74,7 @@ fileprivate struct InspectBuildDescriptionTests {
         }
     }
 
-    @Test(.requireSDKs(.macOS, .iOS))
+    @Test(.requireSDKs(.macOS))
     func artifacts() async throws {
         try await withTemporaryDirectory { (temporaryDirectory: NamedTemporaryDirectory) in
             try await withAsyncDeferrable { deferrable in
@@ -307,7 +307,7 @@ fileprivate struct InspectBuildDescriptionTests {
         }
     }
 
-    @Test(.requireSDKs(.macOS))
+    @Test(.requireSDKs(.macOS, .iOS))
     func selectConfiguredTargets() async throws {
         try await withTemporaryDirectory { (temporaryDirectory: NamedTemporaryDirectory) in
             try await withAsyncDeferrable { deferrable in