zephyr: Add wrapper script for calling twister

Add a wrapper script that helps invoke twister with the correct
configuration and defaults for running EC tests. Developers can simply
run `./twister` from `src/platform/ec` to run all Twister-compatible EC
tests, or specify specific tests to run by adding `-T path/to/testroot`
arguments. Other CLI args are passed straight through to Twister.

This CL also adds a testcase.yaml file to the `math` test, allowing it
to be run through Twister:

```
cd $CROS_WORKON_SRCROOT/src/platform/ec
./twister (or)
./twister -T zephyr/test/math
```

Twister's output directories, `twister-out` and `twister-out.N` have
been added to the `.gitignore`.

The `firmware_builder.py` CQ script now also calls Twister and can merge
in coverage reports.

BRANCH=None
BUG=None
TEST=./twister

Signed-off-by: Tristan Honscheid <honscheid@google.com>
Change-Id: If6ff10ffb76655912c96a66aec28d12dcebd1764
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3773766
Reviewed-by: Yuval Peress <peress@google.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/twister b/twister
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+util/twister_launcher.py
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