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.
1. Rename run-ut.sh to run-be-ut.sh
2. Find all test files from build dir instead of declaring separately in the script
3. Add gtest output to collect the result of unit test.
The upcoming patch will use CREATE_OR_OPEN mode
This patch also remove virtual dtors to cpp file.
* Move the dtors back to env.h
Generally, placing the dtor in an `.h` file(inline) or in a `cpp` file
depends on the trade-off between code expansion and function call overhead.
The code expansion rate is closely related to the number of class members
and the inheritance level.
For the several classes here: `Env`, `ReadableFile`, and `WritableFile`
have no members and are the top level of the inheritance hierarchy, But
for now I have no obvious evidence to prove that make their dtors inline
will cause serious code expansion and more instruction cache-misses,
even if there are thousands of `ReadableFile` objects kept being created
and released during running.
Now Env has unify all environment operation, such as file operation.
However some of our old functions don't leverage it. This change unify
FileUtils::scan_dir to use Env's function.
