Use cached ByteList for infinity and nan Float#to_s

Author: headius

core/src/main/java/org/jruby/RubyFloat.java

@@ -255,10 +255,10 @@ public static IRubyObject induced_from(ThreadContext context, IRubyObject recv,
     public IRubyObject to_s() {
         final Ruby runtime = metaClass.runtime;
         if (Double.isInfinite(value)) {
-            return RubyString.newString(runtime, value < 0 ? "-Infinity" : "Infinity");
+            return RubyString.newStringShared(runtime, value < 0 ? NEGATIVE_INFINITY_TO_S_BYTELIST : POSITIVE_INFINITY_TO_S_BYTELIST);
         }
         if (Double.isNaN(value)) {
-            return RubyString.newString(runtime, "NaN");
+            return RubyString.newStringShared(runtime, NAN_TO_S_BYTELIST);
         }
 
         ByteList buf = new ByteList();
@@ -287,6 +287,10 @@ public IRubyObject to_s() {
         return runtime.newString(buf);
     }
 
+    public static final ByteList POSITIVE_INFINITY_TO_S_BYTELIST = new ByteList(ByteList.plain("Infinity"), USASCIIEncoding.INSTANCE, false);
+    public static final ByteList NEGATIVE_INFINITY_TO_S_BYTELIST = new ByteList(ByteList.plain("-Infinity"), USASCIIEncoding.INSTANCE, false);
+    public static final ByteList NAN_TO_S_BYTELIST = new ByteList(ByteList.plain("NaN"), USASCIIEncoding.INSTANCE, false);
+
     /** flo_coerce
      *
      */