1. Delete Invalid Counter In Data_Stream_Sender. (#3598)
2. Add Counter For PartitionHashTable of PartitionAggregationNode:
* Hash Probe Method
* Row processed by Aggregation
* HashFilledBuckets: Counter How Many FilledBuckets in Aggragation
* HTResize: Counter How Many Resize of HashTable
* HashProbe: Counter Probe of HashTable
* HashFailedProbe: Counter Failed Probe of HashTable
* HashTravelLength: Total TravelLength for Probe
* HashCollisions: Counter of HashCollision
3. Del some unecessary code in PartitionHashTable by template
Remove unused LLVM related codes of directory:be/src/exec (#2910)
there are many LLVM related codes in code base, but these codes are not really used.
The higher version of GCC is not compatible with the LLVM 3.4.2 version currently used by Doris.
The PR delete all LLVM related code of directory: be/src/exec.