build: llvm-tools: replace compiler.host
build: llvm-tools: replace compiler.host

Use `target` instead.

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