Explicitly disable llvm tools for cranelift

compiler/rustc_codegen_cranelift/scripts/setup_rust_fork.sh

@@ -38,6 +38,11 @@ local-rebuild = true
 codegen-backends = ["cranelift"]
 deny-warnings = false
 verbose-tests = false
+# The cg_clif sysroot doesn't contain llvm tools and unless llvm_tools is
+# disabled bootstrap will crash trying to copy llvm tools for the bootstrap
+# compiler.
+llvm_tools = false
+
 EOF
 popd