Add support for simpler test case list syntax

Add support for simpler test case list syntax

This change adds support for mustpass-style (full test case path per
line) test case format. All existing test case list command line options
(--deqp-caselist, --deqp-stdin-caselist, --deqp-caselist-file) now
accept both trie- and list-style inputs.

Format is detected by looking at the first character; trie always starts
with '{', list-style format is assumed otherwise.

de::CommandLine default value behavior has been changed. Options that
take values (i.e. not --flags) don't have value set, unless default
value is provided when registering options. Calling getOption() on
command line option whose value is not provided is now an error.
hasOption() should be used first to check if a value was provided at
all.

Test case list parsing is now covered by tests in the internal module.

Bug: 17958588
Change-Id: If6063165ff59cbd8e538d6f829c583541e104fd1