pgAdmin 4 commit: Fixed feature tests.

Fixed feature tests.
Changes included:
1. Created function for traversing the browser tree.
2. Fixed some synchronization issues.
3. Modified locators.
4. Test cases fix for the recent commits.

Branch
------
master

Details
-------
https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=b48121335c257f4f389832070a5809e2d86919d1
Author: Shubham Agarwal <shubham(dot)agarwal(at)enterprisedb(dot)com>

Modified Files
--------------
web/pgadmin/feature_tests/browser_tool_bar_test.py | 17 +-
.../copy_selected_query_results_feature_test.py | 28 +-
web/pgadmin/feature_tests/file_manager_test.py | 6 +-
.../feature_tests/pg_datatype_validation_test.py | 6 +-
.../pg_utilities_backup_restore_test.py | 34 +-
.../feature_tests/pg_utilities_maintenance_test.py | 30 +-
.../query_tool_auto_complete_tests.py | 6 +-
.../feature_tests/query_tool_journey_test.py | 8 +-
web/pgadmin/feature_tests/query_tool_tests.py | 8 +-
.../feature_tests/table_ddl_feature_test.py | 12 +-
web/pgadmin/feature_tests/view_data_dml_queries.py | 16 +-
.../xss_checks_panels_and_query_tool_test.py | 12 +-
.../xss_checks_pgadmin_debugger_test.py | 17 +-
.../feature_tests/xss_checks_roles_control_test.py | 7 +-
web/regression/feature_utils/locators.py | 19 +-
web/regression/feature_utils/pgadmin_page.py | 423 ++++++++++++++++++---
web/regression/feature_utils/tree_area_locators.py | 92 +++++
.../python_test_utils/test_gui_helper.py | 14 +
18 files changed, 595 insertions(+), 160 deletions(-)