Fix global overrides for any/interface ref types (#1835)

When overriding with any or interface{}, the code should prefer the "any" (empty) schema instead, not the object schema since that's different e.g.

operation.go

@@ -841,9 +841,9 @@ func parseObjectSchema(parser *Parser, refType string, astFile *ast.File) (*spec
 	case refType == NIL:
 		return nil, nil
 	case refType == INTERFACE:
-		return PrimitiveSchema(OBJECT), nil
+		return &spec.Schema{}, nil
 	case refType == ANY:
-		return PrimitiveSchema(OBJECT), nil
+		return &spec.Schema{}, nil
 	case IsGolangPrimitiveType(refType):
 		refType = TransToValidSchemeType(refType)
 

operation_test.go

@@ -2448,15 +2448,16 @@ func TestParseObjectSchema(t *testing.T) {
 
 	schema, err := operation.parseObjectSchema("interface{}", nil)
 	assert.NoError(t, err)
-	assert.Equal(t, schema, PrimitiveSchema(OBJECT))
+	assert.Equal(t, schema, &spec.Schema{})
 
 	schema, err = operation.parseObjectSchema("any", nil)
 	assert.NoError(t, err)
-	assert.Equal(t, schema, PrimitiveSchema(OBJECT))
+	assert.Equal(t, schema, &spec.Schema{})
 
 	schema, err = operation.parseObjectSchema("any{data=string}", nil)
 	assert.NoError(t, err)
-	assert.Equal(t, schema, PrimitiveSchema(OBJECT).SetProperty("data", *PrimitiveSchema("string")))
+	assert.Equal(t, schema,
+		(&spec.Schema{}).WithAllOf(spec.Schema{}, *PrimitiveSchema(OBJECT).SetProperty("data", *PrimitiveSchema("string"))))
 
 	schema, err = operation.parseObjectSchema("int", nil)
 	assert.NoError(t, err)