Go: add test with Argument[0..2] spec

ql/test/library-tests/semmle/go/dataflow/ExternalFlow/sinks.expected

@@ -1,4 +1,5 @@
 invalidModelRow
+| Unrecognized input specification "Argument[0..2]" in sink model. |
 #select
 | test.go:47:10:47:12 | arg | qltest |
 | test.go:48:2:48:13 | type assertion | qltest |

ql/test/library-tests/semmle/go/dataflow/ExternalFlow/sinks.ql

@@ -9,7 +9,8 @@ class SinkModelTest extends SinkModelCsv {
       [
         //`namespace; type; subtypes; name; -; ext; input; kind`
         "github.com/nonexistent/test;B;false;Sink1;;;Argument[0];qltest",
-        "github.com/nonexistent/test;B;false;SinkMethod;;;Argument[-1];qltest"
+        "github.com/nonexistent/test;B;false;SinkMethod;;;Argument[-1];qltest",
+        "github.com/nonexistent/test;B;false;SinkManyArgs;;;Argument[0..2];qltest",
       ]
   }
 }

ql/test/library-tests/semmle/go/dataflow/ExternalFlow/test.go

@@ -140,4 +140,10 @@ func simpleflow() {
 	c4.Set(a.Src1().(string))
 	c4.Set("")
 	b.Sink1(c4.Get()) // $ SPURIOUS: hasTaintFlow="call to Get" // because we currently don't clear content
+
+	arg1 := src
+	arg2 := src
+	arg3 := src
+	arg4 := src
+	b.SinkManyArgs(arg1, arg2, arg3, arg4) // $ hasTaintFlow="arg1" hasTaintFlow="arg2" hasTaintFlow="arg3"
 }

ql/test/library-tests/semmle/go/dataflow/ExternalFlow/vendor/github.com/nonexistent/test/stub.go

@@ -58,6 +58,7 @@ func (a *A1) SrcArg(arg interface{}) {}
 type B interface {
 	Sink1(arg interface{})
 	SinkMethod() interface{}
+	SinkManyArgs(arg1 interface{}, arg2 interface{}, arg3 interface{}, arg4 interface{})
 }
 
 type C struct {