RFR: JDK-8189845: Fix for 8157000 causes significant performance regression

[Kumar Srinivasan]

Hi,

Please review fix to improve javadoc performance regression caused by
fix for  JDK-8157000. The fix removes needless transformations and caches
the result, of a hot method, the performance improvements are documented
in the bug report.

Thanks
Kumar


[1] https://bugs.openjdk.java.net/browse/JDK-8189845
[2] http://cr.openjdk.java.net/~ksrini/8189845/webrev.00/