RFR: 8011350 : hgforesth.sh fails if sh is not bash

[Mike Duigou]

Hello all;

Further testing on JDK-8011342 revealed that hgforest.sh can fail if the sh shell is not bash. The problem appears to be due to mixing of -o -a and ! in [] test expressions.

I have prepared a webrev here:

http://cr.openjdk.java.net/~mduigou/JDK-8011350/0/webrev/common/bin/hgforest.sh.udiff.html

This converts all of the potentially problematic [ expr -o expr ] [ expr -a expr ] and [ expr -{o|a} ! expr ] to use "test". My conversions are based on the advice of the autotools chapter on "Writing portable Bourne Shell" (http://sourceware.org/autobook/autobook/autobook_208.html#SEC208) for avoiding potential problems. 

The other option is just to require bash which is already required by the new build process.

Mike