Just one more benchmark suite (#839)

Adds a dna benchmark

Author: natecook1000

Sources/RegexBenchmark/BenchmarkRegistration.swift

@@ -23,6 +23,7 @@ extension BenchmarkRunner {
     // self.addHTML() // Disabled due to \b being unusably slow
     self.addEmail()
     self.addCustomCharacterClasses()
+    self.addDna()
     self.addBuiltinCC()
     self.addUnicode()
     self.addLiteralSearch()