Switch test_suites to yaml.

This will allow us to include package, url, and argument information in
the engine repo, requiring less infra changes.

The schema of this file should be something like:
test_suites:
 - package: tests-0.far
 - url: fuchsia-pkg://fuchsia.com/tests/meta#tests.cm
 - test_args: -- --gtest_filter=-Test.Disabled

test_args is optional.

See https://fxbug.dev/79691.

Author: chandarrengoog

testing/fuchsia/test_suites

@@ -0,0 +1,4 @@
+# This configuration file specifies test suites along with their gtest filters
+# to be passed as test arguments for flutter on FEMU tests.
+
+test_suites: