add import and tidy fix

Author: Oneirical

tests/run-make/pgo-branch-weights/rmake.rs

@@ -7,7 +7,6 @@
 // If the test passes, the expected function call count was added to the use-phase LLVM-IR.
 // See https://github.com/rust-lang/rust/pull/66631
 
-
 // FIXME(mati865): MinGW GCC miscompiles compiler-rt profiling library but with Clang it works
 // properly. Since we only have GCC on the CI ignore the test for now.
 
@@ -17,6 +16,7 @@
 
 use std::io::{self, Write};
 use std::process::Command;
+use run_make_support::{llvm_profdata, rustc, rustdoc, tmp_dir};
 
 fn main() {
     // For some very small programs GNU ld seems to not properly handle