[OCaml] Some %typecheck precedence tweaks

Fix warnings in overload_numeric.i.

./../overload_numeric.i:36: Warning 509: Overloaded method Nums::over(short) effectively ignored,
./../overload_numeric.i:33: Warning 509: as it is shadowed by Nums::over(signed char).
./../overload_numeric.i:39: Warning 509: Overloaded method Nums::over(int) effectively ignored,
./../overload_numeric.i:33: Warning 509: as it is shadowed by Nums::over(signed char).

Add overload_numeric_runme.ml.

Examples/test-suite/ocaml/overload_numeric_runme.ml

@@ -0,0 +1,14 @@
+open Swig
+open Overload_numeric
+
+let _ =
+  let n = new_Nums '() in
+  let arg = C_char 'c' in
+  assert (n -> over (arg) as string = "signed char");
+  let arg = C_short 2 in
+  assert (n -> over (arg) as string = "short");
+  assert (n -> over (2) as string = "int");
+  let arg = C_float 2. in
+  assert (n -> over (arg) as string = "float");
+  assert (n -> over (2.) as string = "double")
+;;