Hi, please review this enhancement to specialize a few simple and common String concatenation patterns in the default strategy.
Bug: https://bugs.openjdk.java.net/browse/JDK-8222484 Webrev: http://cr.openjdk.java.net/~redestad/8222484/open.00/ This reduces first-time bootstrap times for the targeted patterns from ~20ms to be lost in the noise on my machine (so ~0.5ms), while being peak performance neutral and not regressing bootstrap characteristics on more complex patterns. This also consolidates the String::concat method to reuse the optimized method in StringConcatHelper, which speeds up that method by ~1.4x for a few sampled inputs. Testing: tier1-3 Thanks! /Claes
