Remove excess tests from xmlrs_reader_tests.rs

The following tests in xmlrs_reader_tests.rs already checked by tests in reader-namespaces.rs:
- issue_attributes_have_no_default_namespace   - default_ns_shadowing_empty
- default_namespace_applies_to_end_elem        - default_namespace

The following tests in xmlrs_reader_tests.rs already checked by unit tests src/events/attributes.rs:
- issue_83_duplicate_attributes - `duplicated` modules

tests/xmlrs_reader_tests.rs

@@ -192,23 +192,6 @@ fn tabs_1() {
     );
 }
 
-#[test]
-fn issue_83_duplicate_attributes() {
-    // Error when parsing attributes won't stop main event reader
-    // as it is a lazy operation => add ending events
-    test(
-        r#"<hello><some-tag a='10' a="20"/></hello>"#,
-        "
-            |StartElement(hello)
-            |1:30 EmptyElement(some-tag, attr-error: \
-                  position 16: duplicated attribute, previous declaration at position 9)
-            |EndElement(hello)
-            |EndDocument
-        ",
-        true,
-    );
-}
-
 #[test]
 fn issue_93_large_characters_in_entity_references() {
     test(
@@ -284,20 +267,6 @@ fn issue_105_unexpected_double_dash() {
     );
 }
 
-#[test]
-fn issue_attributes_have_no_default_namespace() {
-    // At the moment, the 'test' method doesn't render namespaces for attribute names.
-    // This test only checks whether the default namespace got applied to the EmptyElement.
-    test(
-        r#"<hello xmlns="urn:foo" x="y"/>"#,
-        r#"
-             |EmptyElement({urn:foo}hello [x="y"])
-             |EndDocument
-         "#,
-        true,
-    );
-}
-
 #[test]
 fn issue_default_namespace_on_outermost_element() {
     // Regression test
@@ -311,22 +280,6 @@ fn issue_default_namespace_on_outermost_element() {
     );
 }
 
-#[test]
-fn default_namespace_applies_to_end_elem() {
-    test(
-        r#"<hello xmlns="urn:foo" x="y">
-              <inner/>
-            </hello>"#,
-        r#"
-            |StartElement({urn:foo}hello [x="y"])
-            |EmptyElement({urn:foo}inner)
-            |EndElement({urn:foo}hello)
-            |EndDocument
-        "#,
-        true,
-    );
-}
-
 #[track_caller]
 fn test(input: &str, output: &str, trim: bool) {
     test_bytes(input.as_bytes(), output.as_bytes(), trim);