TestTools: migrate post.sh and add noerror.sh script

Instead of using command line args to drive the execution of post.sh use the new environment variables that are set by the test executor (see atlasexternals!901 (merged), atlasexternals!908 (merged)).

Also add noerror.sh post-processing script that can be used to check test log files for common errors patterns. This is useful when no full reference file comparison is needed but the output should still be free of errors.

TODO:

• Update https://twiki.cern.ch/twiki/bin/view/AtlasComputing/SoftwareDevelopmentWorkBookCMakeInAtlas once merged.