kunit: tool: parse KTAP compliant test output

kunit: tool: parse KTAP compliant test output

Change the KUnit parser to be able to parse test output that complies with
the KTAP version 1 specification format found here:
https://kernel.org/doc/html/latest/dev-tools/ktap.html. Ensure the parser
is able to parse tests with the original KUnit test output format as
well.

KUnit parser now accepts any of the following test output formats:

Original KUnit test output format:

 TAP version 14
 1..1
   # Subtest: kunit-test-suite
   1..3
   ok 1 - kunit_test_1
   ok 2 - kunit_test_2
   ok 3 - kunit_test_3
 # kunit-test-suite: pass:3 fail:0 skip:0 total:3
 # Totals: pass:3 fail:0 skip:0 total:3
 ok 1 - kunit-test-suite

KTAP version 1 test output format:

 KTAP version 1
 1..1
   KTAP version 1
   1..3
   ok 1 kunit_test_1
   ok 2 kunit_test_2
   ok 3 kunit_test_3
 ok 1 kunit-test-suite

New KUnit test output format (changes made in the next patch of
this series):

 KTAP version 1
 1..1
   KTAP version 1
   # Subtest: kunit-test-suite
   1..3
   ok 1 kunit_test_1
   ok 2 kunit_test_2
   ok 3 kunit_test_3
 # kunit-test-suite: pass:3 fail:0 skip:0 total:3
 # Totals: pass:3 fail:0 skip:0 total:3
 ok 1 kunit-test-suite

Signed-off-by: Rae Moar <rmoar@google.com>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>