Ensure Build is always usable on Ravenwood ...

... even without a RavenwoodRule.

There are situation where android APIs are called outside of
a RavenwoodRule, but some of the APIs require a RavenwoodRule
to initialize them.

Since Build and SystemProperties are critical and often used by
the test infra code (e.g. test runner or other junit rules), make sure
they're always accessible.

Fix: 341735388
Test: atest CtsOsTestCases
Test: $ANDROID_BUILD_TOP/frameworks/base/ravenwood/scripts/run-ravenwood-tests.sh
Change-Id: Iedcfae7e75c5ee9f2c7fb87c61262c2b33450d04