ARM: merge Cyclone into other ARMv8 CPUs and add tests for features.

Cyclone actually supports all the goodies you'd expect to come with an AArch64
CPU, so it doesn't need its own clause. Also we should probably be testing
these clauses.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@236349 91177308-0d34-0410-b5e6-96231b3b80d8