Merge pull request #15108 from darquro/fast-path-ad-hoc-printing-of-strings

[stdlib][SR-7136] Fast-path ad-hoc printing of Strings

Author: CodaFi

stdlib/public/core/OutputStream.swift

@@ -391,6 +391,12 @@ internal func _print_unlocked<T, TargetStream: TextOutputStream>(
     debugPrintable.debugDescription.write(to: &target)
     return
   }
+
+  if let string = value as? String {
+    target.write(string)
+    return
+  }
+
   if case let streamableObject as TextOutputStreamable = value {
     streamableObject.write(to: &target)
     return