Split CtsSignatureTestCases into two CTS packages

CtsSignatureTestCases contained two tests, one for checking the API
signature and one for verifying intents provided by the various
packages to ensure they do not infringe on the android.intent.action
namespace. This splits each test into its own package,
CtsApiSignatureTestCases and CtsIntentSignatureTestCases respectively.

This is in preparation for expanding the CtsApiSignatureTestCases to
test a number of different package configurations, e.g. packages with
and without <use-library android:name="android.test.runner"/>, packages
targeted at an earlier release or the current release, etc.

Tested using:
    m -j32 CtsApiSignatureTestCases && \
        cts-tradefed run cts -a arm64-v8a -m CtsApiSignatureTestCases
And:
    m -j32 CtsIntentSignatureTestCases && \
        cts-tradefed run cts -a arm64-v8a -m CtsIntentSignatureTestCases

Bug: 35192974
Bug: 30188076
Test: see above
Change-Id: I7504f6ddd6e2e73ec111d5b527e85c2a9c74b34d
11 files changed