kunit: improve KTAP compliance of KUnit test output

Change KUnit test output to better comply with KTAP v1 specifications
found here: https://kernel.org/doc/html/latest/dev-tools/ktap.html.
1) Use "KTAP version 1" instead of "TAP version 14" as test output header
2) Remove '-' between test number and test name on test result lines
2) Add KTAP version lines to each subtest header as well

Note that the new KUnit output still includes the “# Subtest” line now
located after the KTAP version line. This does not completely match the
KTAP v1 spec but since it is classified as a diagnostic line, it is not
expected to be disruptive or break any existing parsers. This
“# Subtest” line comes from the TAP 14 spec
(https://testanything.org/tap-version-14-specification.html

) and it is
used to define the test name before the results.

Original output:

 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

New output:

 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>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>