Merge branch 'q9-with-q6' of https://gitlab.eduxiji.net/T202410013993366/DB2024-T202410013993366 into q9-with-q6

# Conflicts:
#	src/execution/execution_manager.cpp
#	src/execution/executor_index_scan.h
#	src/execution/executor_seq_scan.h
#	src/parser/lex.yy.cpp
#	src/parser/lex.yy.hpp
#	src/parser/yacc.tab.cpp
#	src/parser/yacc.tab.h
#	src/parser/yacc.tab.hpp
#	src/parser/yacc.y
#	src/system/sm_manager.h

refactor: Optimize MergeSortJoinExecutor for performance by removing usleep call and increasing the threshold for lazy loading of join buffer

refactor: Optimize MergeSortJoinExecutor for performance by removing usleep call and increasing the threshold for lazy loading of join buffer

refactor: Optimize MergeSortJoinExecutor for performance by removing usleep call and increasing the threshold for lazy loading of join buffer

refactor: Optimize MergeSortJoinExecutor for performance by removing usleep call and increasing the threshold for lazy loading of join buffer

refactor: Optimize MergeSortJoinExecutor for performance by increasing the threshold for lazy loading of join buffer

refactor: Optimize MergeSortJoinExecutor for performance by increasing the threshold for lazy loading of join buffer

refactor: Remove commented out code, update method return type, fix comparison operator, and remove duplicate code