Add LLVM 7.0 ARM/AArch64 backend to CMakeLists.txt
Add LLVM 7.0 ARM/AArch64 backend to CMakeLists.txt

Change-Id: Id4209bfe44d9040e36fe4ea654197211aa1c7ead
Reviewed-on: https://swiftshader-review.googlesource.com/20478
Tested-by: Logan Chien <54d97d247ead2e88f9d88f287e98620efa682c55@google.com>
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>

google/swiftshader,google/swiftshader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader