Fix example logs repeating themselves (#16669)

Move declaration of log streams to before tests, so that results won't get compounded on top of each other

examples/flax/test_flax_examples.py

@@ -70,11 +70,12 @@ def get_results(output_dir, split="eval"):
     return results
 
 
+stream_handler = logging.StreamHandler(sys.stdout)
+logger.addHandler(stream_handler)
+
+
 class ExamplesTests(TestCasePlus):
     def test_run_glue(self):
-        stream_handler = logging.StreamHandler(sys.stdout)
-        logger.addHandler(stream_handler)
-
         tmp_dir = self.get_auto_remove_tmp_dir()
         testargs = f"""
             run_glue.py
@@ -98,9 +99,6 @@ class ExamplesTests(TestCasePlus):
 
     @slow
     def test_run_clm(self):
-        stream_handler = logging.StreamHandler(sys.stdout)
-        logger.addHandler(stream_handler)
-
         tmp_dir = self.get_auto_remove_tmp_dir()
         testargs = f"""
             run_clm_flax.py
@@ -125,9 +123,6 @@ class ExamplesTests(TestCasePlus):
 
     @slow
     def test_run_summarization(self):
-        stream_handler = logging.StreamHandler(sys.stdout)
-        logger.addHandler(stream_handler)
-
         tmp_dir = self.get_auto_remove_tmp_dir()
         testargs = f"""
             run_summarization.py
@@ -158,9 +153,6 @@ class ExamplesTests(TestCasePlus):
 
     @slow
     def test_run_mlm(self):
-        stream_handler = logging.StreamHandler(sys.stdout)
-        logger.addHandler(stream_handler)
-
         tmp_dir = self.get_auto_remove_tmp_dir()
         testargs = f"""
             run_mlm.py
@@ -185,9 +177,6 @@ class ExamplesTests(TestCasePlus):
 
     @slow
     def test_run_t5_mlm(self):
-        stream_handler = logging.StreamHandler(sys.stdout)
-        logger.addHandler(stream_handler)
-
         tmp_dir = self.get_auto_remove_tmp_dir()
         testargs = f"""
             run_t5_mlm_flax.py
@@ -212,9 +201,6 @@ class ExamplesTests(TestCasePlus):
 
     @slow
     def test_run_ner(self):
-        stream_handler = logging.StreamHandler(sys.stdout)
-        logger.addHandler(stream_handler)
-
         # with so little data distributed training needs more epochs to get the score on par with 0/1 gpu
         epochs = 7 if get_gpu_count() > 1 else 2
 
@@ -245,9 +231,6 @@ class ExamplesTests(TestCasePlus):
 
     @slow
     def test_run_qa(self):
-        stream_handler = logging.StreamHandler(sys.stdout)
-        logger.addHandler(stream_handler)
-
         tmp_dir = self.get_auto_remove_tmp_dir()
         testargs = f"""
             run_qa.py