Fix large literals type inference on 32 bits

Some tests are failing because some large literal integers are meant to
be stored on 64 bits, but are stored on 32 on 32 bits architectures.
This causes the value to overflow.

This commit fixes this issue by using explicit int64 typing.

Signed-off-by: Julien Rische <jrische@redhat.com>

decode_test.go

@@ -89,7 +89,7 @@ func TestDecoder(t *testing.T) {
 		},
 		{
 			"v: -0b1000000000000000000000000000000000000000000000000000000000000000",
-			map[string]interface{}{"v": -9223372036854775808},
+			map[string]interface{}{"v": int64(-9223372036854775808)},
 		},
 		{
 			"v: 0xA",
@@ -109,7 +109,7 @@ func TestDecoder(t *testing.T) {
 		},
 		{
 			"v: 4294967296\n",
-			map[string]int{"v": 4294967296},
+			map[string]int64{"v": int64(4294967296)},
 		},
 		{
 			"v: 0.1\n",
@@ -200,7 +200,7 @@ func TestDecoder(t *testing.T) {
 			map[string]uint{"v": 42},
 		}, {
 			"v: 4294967296",
-			map[string]uint64{"v": 4294967296},
+			map[string]uint64{"v": uint64(4294967296)},
 		},
 
 		// int

encode_test.go

@@ -65,7 +65,7 @@ func TestEncoder(t *testing.T) {
 		},
 		{
 			"v: 4294967296\n",
-			map[string]int{"v": 4294967296},
+			map[string]int64{"v": int64(4294967296)},
 			nil,
 		},
 		{