Allow for /proc/cpuinfo files lacking "cpu cores" and/or "siblings" entries.

Borrow code from localeModels/gbt/maxTaskPar to handle the case where
/proc/cpuinfo doesn't have the entries we expect for hyperthreads.
Merge pull request #668 from gbtitus/proc-cpuinfo-no-cores-sibs

Allow for /proc/cpuinfo files lacking "cpu cores" and/or "siblings" entries.
Change sub_test to always use the compileline from CHPL_HOME

compileline can behave poorly if run from a CHPL_TEST_UTIL_DIR that is
not inside of CHPL_HOME when using a module.
Merge pull request #669 from Kyle-B/kb-subtest-compileline

Change sub_test to always use the compileline from CHPL_HOME

compileline can behave poorly if run from a CHPL_TEST_UTIL_DIR that is
not inside of CHPL_HOME when using a module.