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
For the first, we need to make a parameter to discribe the data is local or remote.
At then, we need to support some basic function to support the operation for remote storage.
TabletMeta's _preferred_rowset_type is not initialized after object constructing and
may be a random value, and this field is not updated when create ALPHA_ROWSET tablet,
and it will not be serialized into pb in this case. So if cloning an ALPHA_ROWSET
tablet from another BE, this new created local tablet's _preferred_rowset_type field
may be random as BETA_ROWSET and can not be overwrote after cloned, then new input
rows will be wrote as BETA_ROWSET format which is not we expect.
This patch fix this bug by giving _preferred_rowset_type a default value and updating
this field when create any type of tablet, and add an unit test and related overwrite
equal operator functions.
