Fix some tests that are broken against the latest toolchains.

These are broken either because of parser crashes (due to malformed
input, which we can change easily enough) or due to potential
behavioral changes.

See SR-14552 and SR-14553.

Author: allevato

Tests/SwiftFormatRulesTests/ReturnVoidInsteadOfEmptyTupleTests.swift

@@ -90,18 +90,18 @@ final class ReturnVoidInsteadOfEmptyTupleTests: LintOrFormatRuleTestCase {
       input:
         """
         let callback: () -> /*foo*/()/*bar*/
-        let callback: (Int ->   /*foo*/   ()   /*bar*/) -> ()
+        let callback: ((Int) ->   /*foo*/   ()   /*bar*/) -> ()
         """,
       expected:
         """
         let callback: () -> /*foo*/Void/*bar*/
-        let callback: (Int ->   /*foo*/   Void   /*bar*/) -> Void
+        let callback: ((Int) ->   /*foo*/   Void   /*bar*/) -> Void
         """,
       checkForUnassertedDiagnostics: true
     )
     XCTAssertDiagnosed(.returnVoid, line: 1, column: 28)
-    XCTAssertDiagnosed(.returnVoid, line: 2, column: 35)
-    XCTAssertDiagnosed(.returnVoid, line: 2, column: 52)
+    XCTAssertDiagnosed(.returnVoid, line: 2, column: 37)
+    XCTAssertDiagnosed(.returnVoid, line: 2, column: 54)
   }
 
   func testEmptyTupleWithInternalCommentsIsDiagnosedButNotReplaced() {

Tests/SwiftFormatTests/SyntaxValidatingVisitorTests.swift

@@ -32,16 +32,9 @@ final class SyntaxValidatingVisitorTests: XCTestCase {
     input =
       """
       switch a {
-      case b, c, d: break
       @unknown what_is_this default: break
       }
       """
-    assertInvalidSyntax(in: input, atLine: 3, column: 1)
-
-    input =
-      """
-      @unknown c class Foo {}
-      """
     assertInvalidSyntax(in: input, atLine: 1, column: 1)
   }