cmd/compile: only sort methods/interfaces during export for -d=unifiedquirks

These sorts are only important for 'toolstash -cmp' testing of unified
IR against -G=0 mode, but they were added before I added
-d=unifiedquirks to allow altering small "don't care" output details
like this.

This CL should help mitigate issues with #44195 until package
objectpath is updated and deployed.

Change-Id: Ia3dcf359481ff7abad5ddfca8e673fd2bb30ae01
Reviewed-on: https://go-review.googlesource.com/c/go/+/343390
Trust: Matthew Dempsky <[email protected]>
Run-TryBot: Matthew Dempsky <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Robert Griesemer <[email protected]>

Author: mdempsky

src/cmd/compile/internal/typecheck/iexport.go

@@ -578,7 +578,9 @@ func (p *iexporter) doDecl(n *ir.Name) {
 
 		// Sort methods, for consistency with types2.
 		methods := append([]*types.Field(nil), t.Methods().Slice()...)
-		sort.Sort(types.MethodsByName(methods))
+		if base.Debug.UnifiedQuirks != 0 {
+			sort.Sort(types.MethodsByName(methods))
+		}
 
 		w.uint64(uint64(len(methods)))
 		for _, m := range methods {
@@ -978,8 +980,10 @@ func (w *exportWriter) doTyp(t *types.Type) {
 		// Sort methods and embedded types, for consistency with types2.
 		// Note: embedded types may be anonymous, and types2 sorts them
 		// with sort.Stable too.
-		sort.Sort(types.MethodsByName(methods))
-		sort.Stable(types.EmbeddedsByName(embeddeds))
+		if base.Debug.UnifiedQuirks != 0 {
+			sort.Sort(types.MethodsByName(methods))
+			sort.Stable(types.EmbeddedsByName(embeddeds))
+		}
 
 		w.startType(interfaceType)
 		w.setPkg(t.Pkg(), true)