[fix](memtracking) fix capacity when releasing owned slice

[kaijchen]

Proposed changes

faststring::len_ is data size, faststring::capacity_ is memory size.
Store capacity when building OwnedSlice and fix memtracking when releasing OwnedSlice.

Further comments

If this is a relatively large or complex change, kick off the discussion at dev@doris.apache.org by explaining why you chose the solution you did and what alternatives you considered, etc...

[kaijchen]

run buildall

[github-actions]

clang-tidy made some suggestions

[dataroaring]

LGTM

[github-actions]

PR approved by at least one committer and no changes requested.

[github-actions]

PR approved by anyone and no changes requested.

[xinyiZzz]

LGTM

[yiguolei]

LGTM

[doris-robot]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 44.13 seconds
stream load tsv: 573 seconds loaded 74807831229 Bytes, about 124 MB/s
stream load json: 18 seconds loaded 2358488459 Bytes, about 124 MB/s
stream load orc: 64 seconds loaded 1101869774 Bytes, about 16 MB/s
stream load parquet: 32 seconds loaded 861443392 Bytes, about 25 MB/s
insert into select: 28.9 seconds inserted 10000000 Rows, about 346K ops/s
storage size: 17162397854 Bytes

[doris-robot]

TPC-H test result on machine: 'aliyun_ecs.c7a.8xlarge_32C64G'

Tpch sf100 test result on commit 39f52487f651f362de878ca771adf6256a65d098, data reload: false

run tpch-sf100 query with default conf and session variables
q1	4648	4400	4420	4400
q2	358	142	137	137
q3	1457	1221	1194	1194
q4	1123	916	881	881
q5	3142	3387	3123	3123
q6	251	128	131	128
q7	986	489	481	481
q8	2158	2268	2191	2191
q9	6694	6690	6653	6653
q10	3201	3261	3260	3260
q11	326	206	209	206
q12	351	205	212	205
q13	4564	3843	3895	3843
q14	247	208	210	208
q15	563	529	525	525
q16	440	373	376	373
q17	1018	575	614	575
q18	7854	6885	7367	6885
q19	1512	1380	1419	1380
q20	543	327	324	324
q21	3112	2606	2683	2606
q22	354	283	293	283
Total cold run time: 44902 ms
Total hot run time: 39861 ms

run tpch-sf100 query with default conf and set session variable runtime_filter_mode=off
q1	4395	4360	4370	4360
q2	266	158	178	158
q3	3533	3520	3512	3512
q4	2384	2376	2365	2365
q5	5748	5731	5739	5731
q6	237	121	122	121
q7	2362	1883	1864	1864
q8	3510	3509	3532	3509
q9	9034	8992	8994	8992
q10	3919	3988	3971	3971
q11	501	386	386	386
q12	758	592	593	592
q13	4311	3550	3579	3550
q14	278	253	241	241
q15	573	512	525	512
q16	479	427	462	427
q17	1879	1871	1820	1820
q18	8650	8216	8290	8216
q19	1735	1747	1738	1738
q20	2253	1961	1939	1939
q21	6493	6144	6112	6112
q22	509	424	419	419
Total cold run time: 63807 ms
Total hot run time: 60535 ms