Revert "[release-branch.go1.10] cmd/compile/internal/gc: OMUL should be evaluated when using soft-float"

This reverts commit d74e69c7553fcb1e057821a089dc4f2c60f42e5d.

Reason for revert: this fix has been backported to 1.11, and that makes
it ineligible for backport to 1.10, since upgrading to 1.11 is a valid
workaround according to https://github.com/golang/go/wiki/MinorReleases.

Also, this triggers a bug on Wasm that would require a backport of
CL 149965, too.

Updates #28688
Updates #28959

Change-Id: I4e56554ea27b5db83bdb1e9d2103dd24e3da8cfc
Reviewed-on: https://go-review.googlesource.com/c/154297
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index eee5a37..e0925dc 100644
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -1168,7 +1168,7 @@
 
 	// When using soft-float, these ops might be rewritten to function calls
 	// so we ensure they are evaluated first.
-	case OADD, OSUB, OMINUS, OMUL:
+	case OADD, OSUB, OMINUS:
 		if thearch.SoftFloat && (isFloat[n.Type.Etype] || isComplex[n.Type.Etype]) {
 			return true
 		}
diff --git a/test/fixedbugs/issue28688.go b/test/fixedbugs/issue28688.go
deleted file mode 100644
index 0d2000e..0000000
--- a/test/fixedbugs/issue28688.go
+++ /dev/null
@@ -1,31 +0,0 @@
-// run -gcflags=-d=softfloat
-
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package main
-
-import (
-	"fmt"
-)
-
-// When using soft-float, OMUL might be rewritten to function
-// call so we should ensure it was evaluated first. Stack frame
-// setup for "test" function call should happen after call to runtime.fmul32
-
-var x int32 = 1
-
-func main() {
-	var y float32 = 1.0
-	test(x, y*y)
-}
-
-//go:noinline
-func test(id int32, a float32) {
-
-	if id != x {
-		fmt.Printf("got: %d, want: %d\n", id, x)
-		panic("FAIL")
-	}
-}