RFR: 8152074: Avoid lambda usage in StringConcatFactory initializer

[Claes Redestad]

Hi,

please review this patch to remove lambda usage in the 
StringConcatFactory initializer, which saves some parts of 
java.lang.invoke infrastructure initialization for later.

Bug: https://bugs.openjdk.java.net/browse/JDK-8152074
Webrev: http://cr.openjdk.java.net/~redestad/8152074/webrev.01/

This seem to help address execution times in certain tests when running 
on fastdebug builds: https://bugs.openjdk.java.net/browse/JDK-8151887

Thanks!

/Claes