Duplicate TestTextScanRangeLengths in test_scanners.py

There is a duplicate TestTextScanRangeLengths class in test_scanners.py

https://github.com/apache/impala/blob/248060528abd7fb5425f519ee1608598ed2d3ac3/tests/query_test/test_scanners.py#L1377

https://github.com/apache/impala/blob/248060528abd7fb5425f519ee1608598ed2d3ac3/tests/query_test/test_scanners.py#L1494 

The name should be unique for both test class within same file to run properly.

Simple grep found another duplicates at TestObservability and TestCompactCatalogUpdates. These other duplicates does not cause issue because they are defined in separate test files: test_local_catalog.py, test_observability.py, and test_compact_catalog_updates.py. But ideally they should be distinguishable.

$ git grep "^class Test" tests/ | cut -d":" -f2 | sort |uniq -c | sort | tail -n 5
      1 class TestZippingUnnestFromView(ImpalaTestSuite)
      1 class TestZippingUnnest(ImpalaTestSuite)
      2 class TestCompactCatalogUpdates(CustomClusterTestSuite)
      2 class TestObservability(CustomClusterTestSuite)
      2 class TestTextScanRangeLengths(ImpalaTestSuite)