test/parser: Update test cases as per new parser requesting conf files

Update the parser test code/cases as per new prototyping of parse()
function which doesn't require buf and len to be passed from the caller,
instead reading the configuration data either embedded or from file to
a parser's known conffile.

Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>