[MNG-1927] This adds the test mojos required to fix ${pom.build.*} expansion to full paths, the problem was the new interpolator so the one from 2.0 was used and some envar handling was back ported. Unit tests have been added for envar handling as well as an IT. The maven-core-it script will now set an envar which is used in it0090.
maven/components/trunk/integration-tests/maven-core-it-plugin/src/main/java/org/apache/maven/plugin/coreit/InterpolatedEnvarConfigurationMojo.java
maven/components/trunk/maven-core-it/it0090/