misc/cgo/test: add test for issue 31093

Updates #31093

Change-Id: I7962aaca0b012de01768b7b42dc2283d5845eeea
Reviewed-on: https://go-review.googlesource.com/c/go/+/180377
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

misc/cgo/test/test.go

@@ -849,6 +849,9 @@ static int f29748(S29748 *p) { return 0; }
 static void issue29781F(char **p, int n) {}
 #define ISSUE29781C 0
 
+// issue 31093
+static uint16_t issue31093F(uint16_t v) { return v; }
+
 */
 import "C"
 
@@ -2073,3 +2076,10 @@ func test30065(t *testing.T) {
 		t.Errorf("&d[0] failed: got %c, want %c", d[0], 'c')
 	}
 }
+
+// issue 31093
+// No runtime test; just make sure it compiles.
+
+func Issue31093() {
+	C.issue31093F(C.ushort(0))
+}