Avoid adding compiler-used functions to symbols.o

Author: dianqk

src/bin/miri.rs

@@ -165,6 +165,7 @@ impl rustc_driver::Callbacks for MiriBeRustCompilerCalls {
                                     level: SymbolExportLevel::C,
                                     kind: SymbolExportKind::Text,
                                     used: false,
+                                    used_compiler: false,
                                 },
                             ))
                         }),