cue: add an attribute test with a non-Go integer literal

10Mi is a valid CUE integer literal per the spec section
https://cuelang.org/docs/reference/spec/#numeric-literals
but it is not a valid Go integer literal.

The following commit resolves a TODO to use cue/literal for parsing
numbers from attributes, changing the behavior of this test.

Signed-off-by: Daniel Martí <mvdan@mvdan.cc>
Change-Id: I8ea07d0fa5bb2eb1c8ce293c16387395c954dfaf
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1204903
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
Reviewed-by: Paul Jolly <paul@myitcv.io>

cue/attribute_test.go

@@ -293,6 +293,7 @@ func TestAttributeInt(t *testing.T) {
 	a: {
 		a: 0 @foo(1,3,c=1)
 		b: 1 @bar(a,-4,c,d=1) @foo(a,,d=1)
+		c: 2 @nongo(10Mi)
 	}
 	`
 	testCases := []struct {
@@ -325,6 +326,11 @@ func TestAttributeInt(t *testing.T) {
 		attr: "foo",
 		pos:  2,
 		err:  errors.New(`strconv.ParseInt: parsing "c=1": invalid syntax`),
+	}, {
+		path: "c",
+		attr: "nongo",
+		pos:  0,
+		err:  errors.New(`strconv.ParseInt: parsing "10Mi": invalid syntax`),
 	}}
 	for _, tc := range testCases {
 		cuetdtest.FullMatrix.Run(t, fmt.Sprintf("%s.%s:%d", tc.path, tc.attr, tc.pos), func(t *testing.T, m *cuetdtest.M) {