Check for missing supported param for annotations

Caught by aidl_parser_fuzzer. The std::vector at() call was crashing
when trying to create a string out of something that didn't exist.
The failure in this test case now reads:
Parameter V not supported for annotation Backing. It must be one of: type

Test: aidl_parser_fuzer $TEST_CASE_FROM_BUG
Bug: 155358288
Change-Id: I51269d98a65b0d76e6e7e35a61b1645f4962c61d
2 files changed