add some tests

dbms/tests/queries/0_stateless/01055_compact_parts_1.sql

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+drop table if exists mt_compact;
+
+create table mt_compact (a Int, s String) engine = MergeTree order by a partition by a
+settings index_granularity_bytes = 0;
+alter table mt_compact modify setting min_rows_for_wide_part = 1000; -- { serverError 48 }
+
+create table mt_compact_2 (a Int, s String) engine = MergeTree order by a partition by a
+settings min_rows_for_wide_part = 1000;
+insert into mt_compact_2 values (1, 'a');
+alter table mt_compact attach partition 1 from mt_compact_2; -- { serverError 36 }

dbms/tests/queries/0_stateless/01055_compact_parts_granularity.reference

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+100
+1	9

dbms/tests/queries/0_stateless/01055_compact_parts_granularity.sql

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+drop table if exists mt_compact;
+
+-- Checks that granularity correctly computed from small parts.
+
+create table mt_compact(a Int, s String) engine = MergeTree order by a
+settings min_rows_for_wide_part = 1000,
+index_granularity = 14;
+
+system stop merges mt_compact;
+set max_block_size = 1;
+set min_insert_block_size_rows=1;
+insert into mt_compact select number, 'aaa' from numbers(100);
+
+select count() from system.parts where table = 'mt_compact' and database = currentDatabase() and active;
+
+system start merges mt_compact;
+optimize table mt_compact final;
+
+select count(), sum(marks) from system.parts where table = 'mt_compact' and database = currentDatabase() and active;
+
+drop table mt_compact;