make mark_span_for_resize inert for perf comparison

Author: estebank

compiler/rustc_middle/src/ty/mod.rs

@@ -2400,7 +2400,11 @@ impl<'tcx> TyCtxt<'tcx> {
     /// `Span` before it was changed. This is used today only to be able to identify `Span`s coming
     /// from a proc-macro even when it was modified, to avoid giving spurious suggestions when the
     /// `Span` points at an attribute and not user code.
+    #[inline(always)]
     pub fn mark_span_for_resize(self, span: Span) -> Span {
+        if true {
+            return span;
+        }
         self.with_stable_hashing_context(|hcx| {
             span.mark_with_reason(None, rustc_span::DesugaringKind::Resize, span.edition(), hcx)
         })