Surface entity_map_match error if expectResult fails

The entity_map_match error contains relevant information about the failed match (e.g. field path). This is consistent with error reporting for error.expectResult later in the function.

Author: jmikola

src/libmongoc/tests/unified/result.c

@@ -368,10 +368,10 @@ result_check (result_t *result,
                              result->value,
                              result->array_of_root_docs,
                              error)) {
-         test_set_error (error,
-                         "expectResult mismatch:\nExpected: %s\nActual: %s\n",
-                         bson_val_to_json (expect_result),
-                         bson_val_to_json (result->value));
+         test_diagnostics_error_info (
+            "expectResult mismatch:\nExpected: %s\nActual: %s\n",
+            bson_val_to_json (expect_result),
+            bson_val_to_json (result->value));
          goto done;
       }
    }