[gclient] Use lowercase and when merging conditions

python doesn't understand AND.

R=jojwang@google.com

Change-Id: Icd0a8a4440bea2e272b2e9760bcd88a65d559848
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5555884
Reviewed-by: Joanna Wang <jojwang@chromium.org>
Auto-Submit: Josip Sokcevic <sokcevic@chromium.org>
Commit-Queue: Joanna Wang <jojwang@chromium.org>

gclient_utils.py

@@ -1397,5 +1397,5 @@ def merge_conditions(*conditions):
         if not condition:
             condition = current_condition
             continue
-        condition = f'({condition}) AND ({current_condition})'
+        condition = f'({condition}) and ({current_condition})'
     return condition

tests/gclient_utils_test.py

@@ -408,10 +408,10 @@ class GClientUtilsTest(trial_dir.TestCase):
 
         self.assertEqual('foo', gclient_utils.merge_conditions(None, 'foo'))
 
-        self.assertEqual('(foo) AND (bar)',
+        self.assertEqual('(foo) and (bar)',
                          gclient_utils.merge_conditions('foo', 'bar'))
 
-        self.assertEqual('(foo or bar) AND (baz)',
+        self.assertEqual('(foo or bar) and (baz)',
                          gclient_utils.merge_conditions('foo or bar', 'baz'))
 
 if __name__ == '__main__':