run serial test even when parallel test fails
run serial test even when parallel test fails

The serial test won't run when parallel group fails
because of the short-circuiting effect of logical
operators.

Assuming the tool was not designed to fail the whole
test prematurely, this change ensures both test groups
executed every time.

BUG=None
TEST=build_test and observe the test cases in serial
group (io_jail and sys_util) are executed when the
parallel group fails.

Change-Id: I86e57069490c58dfed48960d87ea35c2403450b7
Signed-off-by: Jianxun Zhang <cf37b857570b0701d39fd0feb77f6a52483b5c8d@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/1488611
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Zach Reizner <3374927928a53d04457674c546bd4de57c2044ec@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm