test: add mipsx case to nosplit.go

Change-Id: I496bceacb6b3f417e36dc725d988b12c59a200d5
Reviewed-on: https://go-review.googlesource.com/34412Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

test/nosplit.go

@@ -261,6 +261,8 @@ TestCases:
 		var buf bytes.Buffer
 		ptrSize := 4
 		switch goarch {
+		case "mips", "mipsle":
+			fmt.Fprintf(&buf, "#define CALL JAL\n#define REGISTER (R0)\n")
 		case "mips64", "mips64le":
 			ptrSize = 8
 			fmt.Fprintf(&buf, "#define CALL JAL\n#define REGISTER (R0)\n")