[optimization] Optimize hash table build

[stdpain]

Describe
In the original logic, Hashtable uses a vector-like structure to store actual data. When constructing the hash table, there may be about a quarter of the time copying data continuously. Especially in the case of building more columns, it will take more time. So I changed this to a raw pointer to avoid extra copy overhead. There will be good results in the hash table construction phase

Here is my test case, LINE_ORDER and LINE_ORDER_V2 is from SSB datasets:

SELECT count(*) FROM LINE_ORDER t1 join LINE_ORDER_V2 t2 WHERE t1.LO_ORDERKEY=t2.LO_ORDERKEY;

Type	Right Table Rows	Build Time	Probe Time	Time Cost (s)
After	6001215	658.288ms	1s451ms	4.07
Before	6001215	1s428ms	1s512ms	4.69