Include llvm-as in llvm-tools-preview component
Include llvm-as in llvm-tools-preview component

Including llvm-as adds the ability to include assembly language fragments
that can be inlined using LTO.

graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust