Don’t emit messages about mismatched diagnostic messages if the diagnostic count doesn’t match

Author: ahoppen

Tests/SwiftParserTest/Assertions.swift

@@ -244,9 +244,10 @@ func AssertParse<Node: RawSyntaxNodeProtocol>(
         Expected \(expectedDiagnostics.count) diagnostics but received \(diags.count):
         \(diags.map(\.debugDescription).joined(separator: "\n"))
         """, file: file, line: line)
-      }
-      for (diag, expectedDiag) in zip(diags, expectedDiagnostics) {
-        AssertDiagnostic(diag, in: tree, markerLocations: markerLocations, expected: expectedDiag, file: expectedDiag.file, line: expectedDiag.line)
+      } else {
+        for (diag, expectedDiag) in zip(diags, expectedDiagnostics) {
+          AssertDiagnostic(diag, in: tree, markerLocations: markerLocations, expected: expectedDiag, file: expectedDiag.file, line: expectedDiag.line)
+        }
       }
 
       // Applying Fix-Its