Code Review: irtests_parallel

FYI Review:
tfpt review “/shelveset:irtests_parallel;REDMOND\jdeville”
Comment :
cmd /k caused irtests to hang for non-parallel processes. So I made
the /k conditional on passing in the parallel option.

tfpt review /shelveset:irtests;sborde

Disables tests failing on Ivan’s build machine. The
DateExtCalculationsTest test is failing on the build machine with MRI as
well, so the test needs more investigation. The Dir.chdir issues are a
bug in IronRuby. We want to keep testing with TMP set to a long path
name (instead of working around the bug by setting TMP to something
short) so that we have coverage from the other tests to ensure that
there are no other issues with TMP being set to a long path name.