speccpu/x264: add recompile_mc_src to simplify code

src/speccpu/x264.py

@@ -203,3 +203,18 @@ def perf_ref(x264_run, perf_output):
         ],
         cwd=x264_run,
     )
+
+
+def recompile_mc_src(mc_src: str, x264_build: Path, spec_env: Mapping[str, str]):
+    mc_path = get_mc_path(x264_build)
+    assert mc_path.exists()
+
+    # Write mc_src to mc_path, recompile it, and replace resulting exe
+    with open(mc_path, "w") as f:
+        f.write(mc_src)
+
+    # Recompile
+    recompiled_x264_path = recompile_mc(mc_path, x264_build, spec_env)
+    assert recompiled_x264_path.exists()
+    assert recompiled_x264_path.is_file()
+    return recompiled_x264_path