Add tests for the PMCGROUPINHERITMISS log record.

A fixture writes a log file that holds the record, so the parser tests
do not need a PMU or root. Two tests then read it: one checks the
libpmc parser and the text form, and one checks the JSON conversion.
A shell test runs pmcstat(8) over the fixture file and checks that it
reports the record.

Sponsored by: AMD

Signed-off-by: Andre Silva <andasilv@amd.com>