Currently, there are 2 status code in BE, one is common/Status.h,
and the other is olap/olap_define.h called OLAPStatus.
OLAPStatus is just an enum type, it is very simple and could not save many informations,
I will unify these code to common/Status.
1. solved the previous delayed unit test file size is too large (1.7G+) and the unit test link time is too long problem problems
2. Unify all unit tests into one file to significantly reduce unit test execution time to less than 3 mins
3. temporarily disable stream_load_test.cpp, metrics_action_test.cpp, load_channel_mgr_test.cpp because it will re-implement part of the code and affect other tests
I met a failure of reading hdfs files in broker load, the error message is unclear and
I spent a lot of time to locate the problem.
```
W0330 11:08:01.093812 2755268 broker_scan_node.cpp:364] Scanner[0] process failed. status=connect failed.
W0330 11:08:01.097682 2018787 fragment_mgr.cpp:234] Got error while opening fragment 712ae2b848324cb6-94a83d646173c1e9: Internal error: connect failed.
W0330 11:08:01.097702 2018787 tablet_sink.cpp:148] connect failed.
```
We should add more information when connect to hdfs failed.
Current situation of Doris is that the cluster is balanced, but the disks of a backend may be unbalanced.
for example, backend A have two disks: disk1 and disk2, disk1's usage is 98%, but disk2's usage is only 40%.
disk1 is unable to take more data, therefore only one disk of backend A can take new data,
the available write throughput of backend A is only half of its ability, and we can not resolve this through load or
partition rebalance now.
So we introduce disk rebalancer, disk rebalancer is different from other rebalancer(load or partition)
which take care of cluster-wide data balancing. it takes care about backend-wide data balancing.
[For more details see #8550](https://github.com/apache/incubator-doris/issues/8550)
Add a new column-type to speed up the approximation of quantiles.
1. The new column-type is named `quantile_state` with fixed aggregation function `quantile_union`, which stores the intermediate results of pre-aggregated approximation calculations for quantiles.
2. support pre-aggregation of new column-type and quantile_state related functions.
Early Design Documentation: https://shimo.im/docs/DT6JXDRkdTvdyV3G
Implement a new way of memory statistics based on TCMalloc New/Delete Hook,
MemTracker and TLS, and it is expected that all memory new/delete/malloc/free
of the BE process can be counted.
Modify the implementation of MemTracker:
1. Simplify a lot of useless logic;
2. Added MemTrackerTaskPool, as the ancestor of all query and import trackers, This is used to track the local memory usage of all tasks executing;
3. Add cosume/release cache, trigger a cosume/release when the memory accumulation exceeds the parameter mem_tracker_consume_min_size_bytes;
4. Add a new memory leak detection mode (Experimental feature), throw an exception when the remaining statistical value is greater than the specified range when the MemTracker is destructed, and print the accurate statistical value in HTTP, the parameter memory_leak_detection
5. Added Virtual MemTracker, cosume/release will not sync to parent. It will be used when introducing TCMalloc Hook to record memory later, to record the specified memory independently;
6. Modify the GC logic, register the buffer cached in DiskIoMgr as a GC function, and add other GC functions later;
7. Change the global root node from Root MemTracker to Process MemTracker, and remove Process MemTracker in exec_env;
8. Modify the macro that detects whether the memory has reached the upper limit, modify the parameters and default behavior of creating MemTracker, modify the error message format in mem_limit_exceeded, extend and apply transfer_to, remove Metric in MemTracker, etc.;
Modify where MemTracker is used:
1. MemPool adds a constructor to create a temporary tracker to avoid a lot of redundant code;
2. Added trackers for global objects such as ChunkAllocator and StorageEngine;
3. Added more fine-grained trackers such as ExprContext;
4. RuntimeState removes FragmentMemTracker, that is, PlanFragmentExecutor mem_tracker, which was previously used for independent statistical scan process memory, and replaces it with _scanner_mem_tracker in OlapScanNode;
5. MemTracker is no longer recorded in ReservationTracker, and ReservationTracker will be removed later;
There are 3 error code types in BE: OLAPStatus AgentStatus Status.
It is very confused and sometimes conflict during write code.
I will try to unify them to Status.
* [refactor] remove types_test
1. remove types_test, it will cause core dump in higher version GCC or
clang, because of memory align, some code will be vectorized in higher
GCC or clang
2. Change string type length to 2 GB instead of -1
3. modify inaccessible code
