Removing empty error tests - c_default_error

C default arguments are allowed, so migrated the error test to a proper test,
as no error or warning is expected.

Examples/test-suite/default_args_c.i

@@ -0,0 +1,14 @@
+%module default_args_c
+
+/* Default arguments for C code */
+int foo1(int x = 42 || 3);
+int foo43(int x = 42 | 3);
+
+%{
+int foo1(int x) {
+  return x;
+}
+int foo43(int x) {
+  return x;
+}
+%}

Examples/test-suite/errors/c_default_error.i

@@ -1,4 +0,0 @@
-%module xxx
-
-int foo(int x = 42 || 3);
-

Examples/test-suite/python/default_args_c_runme.py

@@ -0,0 +1,6 @@
+import default_args_c
+
+if default_args_c.foo1() != 1:
+  raise RuntimeError("failed")
+if default_args_c.foo43() != 43:
+  raise RuntimeError("failed")