OpenMax AL / SL ES tests: no foldable states

Add annotations for the CtsNativeMediaXaTestCases and
CtsNativeMediaSlTestCases test suites to indicate they are
not dependent on the foldable state (if any) of the DUT.

Bug: 197814398
Bug: 197813825
Test: this is the test
Change-Id: I562cfb08a3bc171f3b6d5fe699fd405d66b37e8f
Merged-In: I562cfb08a3bc171f3b6d5fe699fd405d66b37e8f