Rollup merge of #78706 - bjorn3:fix_run_make_without_llvm, r=Mark-Simulacrum
Rollup merge of #78706 - bjorn3:fix_run_make_without_llvm, r=Mark-Simulacrum

Fix run-make tests running when LLVM is disabled

The `--cc`, `--cxx`, `--cflags` and `--ar` flags were only passed to compiletest when `builder.config.llvm_enabled()` returned true. This is preventing me from running the tests on cg_clif.

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