Do less test_ptrack_eat_my_data iterations to don't hit travis timeout limit

Author: ololobus

.travis.yml

@@ -26,4 +26,4 @@ env:
     - PG_VERSION=12 PG_BRANCH=REL_12_STABLE TEST_CASE=all
     - PG_VERSION=12 PG_BRANCH=REL_12_STABLE TEST_CASE=all MODE=paranoia
     - PG_VERSION=12 PG_BRANCH=REL_12_STABLE TEST_CASE=test_ptrack_multiple_segments TEST_REPEATS=5 MODE=paranoia
-    - PG_VERSION=12 PG_BRANCH=REL_12_STABLE TEST_CASE=test_ptrack_eat_my_data TEST_REPEATS=5
+    - PG_VERSION=12 PG_BRANCH=REL_12_STABLE TEST_CASE=test_ptrack_eat_my_data TEST_REPEATS=4