[Ravenwood] Relax the test method name validator

Previously, the validator didn't allow this:

@Before public testSetUp() {...}

It'd say "testSetUp() should have @Test".

But I see this naming pattern in ICU, so let's allow it.

Bug: 292141694
Test: $ANDROID_BUILD_TOP/frameworks/base/ravenwood/scripts/run-ravenwood-tests.sh
Flag: EXEMPT host side test change only
Change-Id: Ifef932cb07816bac9edb624a725accbbf8e7d63d