In run_tests.py, display "XPASS" before "FAIL" in the summaries because "FAIL" is the more interesting and we want to display the results in order from least interesting to most interesting. Also make cosmetic changes in that code.
In run_tests.py, display "XPASS" before "FAIL" in the summaries because "FAIL"
is the more interesting and we want to display the results in order from least
interesting to most interesting. Also make cosmetic changes in that code.

* build/run_tests.py
  (run): Move "XPASS" before "FAIL" in the summaries. Unconditionally print the
    summaries header line because we never expect all the summaries (including
    the number of tests that passed) to be empty. Tidy the code. Expand the doc
    string.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@880125 13f79535-47bb-0310-9956-ffa450edef68

wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion