RFR: 8157102: Avoid exceptional control flow in Configuration.getText

[Claes Redestad]

Hi,

please review this patch to avoid using exceptional control flow in 
.../doclets/internal/toolkit/Configuration.java

Webrev: http://cr.openjdk.java.net/~redestad/8157102/webrev.01/
Bug: https://bugs.openjdk.java.net/browse/JDK-8157102

This improves javadoc performance across a range of workloads.

Thanks!

/Claes