MB-42981: Remove chk_period setting from CheckpointRemoverTest

CheckpointRemoverTest does not need the explicit setting as the
parent test fixture now forces chk_period to be a large value.

Patch also includes an improvement to output when store_item
fails.

Change-Id: I19f492c16f865d6c1fd26483ea15dfe77b158b05
Reviewed-on: http://review.couchbase.org/c/kv_engine/+/142752
Reviewed-by: Paolo Cocchi <paolo.cocchi@couchbase.com>
Tested-by: Build Bot <build@couchbase.com>

engines/ep/tests/module_tests/checkpoint_remover_test.cc

@@ -30,9 +30,6 @@
 #include "test_helpers.h"
 
 void CheckpointRemoverTest::SetUp() {
-    // Set a large period for checkpoint creation so that time isn't a factor
-    // in checkpoint creation, triggering spurious failures
-    config_string += "chk_period=10000";
     SingleThreadedKVBucketTest::SetUp();
 }
 

engines/ep/tests/module_tests/kv_bucket_test.cc

@@ -159,7 +159,8 @@ Item KVBucketTest::store_item(Vbid vbid,
     auto expectedCount = std::count(
             expected.begin(), expected.end(), cb::engine_errc(returnCode));
     EXPECT_NE(0, expectedCount)
-            << "unexpected error:" << cb::to_engine_errc(returnCode);
+            << "unexpected error:" << cb::to_engine_errc(returnCode)
+            << " for key:" << key.to_string();
     return item;
 }