kunit: tool: make parser preserve whitespace when printing test log

kunit: tool: make parser preserve whitespace when printing test log

Currently, kunit_parser.py is stripping all leading whitespace to make
parsing easier. But this means we can't accurately show kernel output
for failing tests or when the kernel crashes.

Embarassingly, this affects even KUnit's own output, e.g.
[13:40:46] Expected 2 + 1 == 2, but
[13:40:46] 2 + 1 == 3 (0x3)
[13:40:46] not ok 1 example_simple_test
[13:40:46] [FAILED] example_simple_test

After this change, here's what the output in context would look like
[13:40:46] =================== example (4 subtests) ===================
[13:40:46] # example_simple_test: initializing
[13:40:46] # example_simple_test: EXPECTATION FAILED at lib/kunit/kunit-example-test.c:29
[13:40:46] Expected 2 + 1 == 2, but
[13:40:46]     2 + 1 == 3 (0x3)
[13:40:46] [FAILED] example_simple_test
[13:40:46] [SKIPPED] example_skip_test
[13:40:46] [SKIPPED] example_mark_skipped_test
[13:40:46] [PASSED] example_all_expect_macros_test
[13:40:46]     # example: initializing suite
[13:40:46] # example: pass:1 fail:1 skip:2 total:4
[13:40:46] # Totals: pass:1 fail:1 skip:2 total:4
[13:40:46] ===================== [FAILED] example =====================

This example shows one minor cosmetic defect this approach has.
The test counts lines prevent us from dedenting the suite-level output.
But at the same time, any form of non-KUnit output would do the same
unless it happened to be indented as well.

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