[AArch64][ARM] Context sensitive meaning of crypto

For AArch64, crypto means:
- sm4 + sha3 + sha2 + aes for Armv8.4-A and up, and
- sha2 + aes for Armv8.3-A and earlier.

For AArch32:
Crypto means sha2 + aes, because the Armv8.2-A crypto instructions
were added to AArch64 only.

Differential Revision: https://reviews.llvm.org/D50179

llvm-svn: 343758