Implemented function arrayElement for generic case; partially removed bad code [#METR-22008].

dbms/tests/queries/0_stateless/00343_array_element_generic.reference

+0
+0
+1
+1
+1
+1
+1
+1
+1
+1
+0
+0
+1
+2
+3
+4
+5
+6
+7
+8
+0
+0
+1
+2
+3
+4
+5
+6
+7
+8
+0
+0
+0
+2
+2
+2
+2
+2
+2
+2
+
+
+1
+1
+1
+1
+1
+1
+1
+1
+
+0
+1
+2
+3
+4
+5
+6
+7
+8
+
+0
+1
+2
+3
+4
+5
+6
+7
+8
+
+0
+
+2
+2
+2
+2
+2
+2
+2
+[]
+[]
+[0]
+[0]
+[0]
+[0]
+[0]
+[0]
+[0]
+[0]
+[]
+[]
+[0]
+[0,1]
+[0,1,2]
+[0,1,2,3]
+[0,1,2,3,4]
+[0,1,2,3,4,5]
+[0,1,2,3,4,5,6]
+[0,1,2,3,4,5,6,7]
+[]
+[]
+[0]
+[0,1]
+[0,1,2]
+[0,1,2,3]
+[0,1,2,3,4]
+[0,1,2,3,4,5]
+[0,1,2,3,4,5,6]
+[0,1,2,3,4,5,6,7]
+[]
+[]
+[]
+[0,1]
+[0,1]
+[0,1]
+[0,1]
+[0,1]
+[0,1]
+[0,1]
+[1]	[1]	[1]	[1]
+['Hello']	['World']	['Hello']	['World']
+[]	[]	
+[['a'],['b','c']]	['a']	a
+[['d','e','f'],['g','h','i','j'],['k','l','m','n','o']]	['g','h','i','j']	h
+[['p','q','r','s','t','u'],['v','w','x','y','z','aa','bb'],['cc','dd','ee','ff','gg','hh','ii','jj'],['kk','ll','mm','nn','oo','pp','qq','rr','ss']]	['cc','dd','ee','ff','gg','hh','ii','jj']	ee
+[]	[]	
+[]	[]	
+[]	[]	
+[]	[]	
+[]	[]	
+[]	[]	

dbms/tests/queries/0_stateless/00343_array_element_generic.sql

+SELECT range(number)[2] FROM system.numbers LIMIT 10;
+SELECT range(number)[-1] FROM system.numbers LIMIT 10;
+SELECT range(number)[number] FROM system.numbers LIMIT 10;
+SELECT range(number)[2 - number] FROM system.numbers LIMIT 10;
+
+SELECT arrayMap(x -> toString(x), range(number))[2] FROM system.numbers LIMIT 10;
+SELECT arrayMap(x -> toString(x), range(number))[-1] FROM system.numbers LIMIT 10;
+SELECT arrayMap(x -> toString(x), range(number))[number] FROM system.numbers LIMIT 10;
+SELECT arrayMap(x -> toString(x), range(number))[2 - number] FROM system.numbers LIMIT 10;
+
+SELECT arrayMap(x -> range(x), range(number))[2] FROM system.numbers LIMIT 10;
+SELECT arrayMap(x -> range(x), range(number))[-1] FROM system.numbers LIMIT 10;
+SELECT arrayMap(x -> range(x), range(number))[number] FROM system.numbers LIMIT 10;
+SELECT arrayMap(x -> range(x), range(number))[2 - number] FROM system.numbers LIMIT 10;
+
+SELECT [[1]][1], materialize([[1]])[1], [[1]][materialize(1)], materialize([[1]])[materialize(1)];
+SELECT [['Hello']][1], materialize([['World']])[1], [['Hello']][materialize(1)], materialize([['World']])[materialize(1)];
+
+SELECT ([[['a'], ['b', 'c']], [['d', 'e', 'f'], ['g', 'h', 'i', 'j'], ['k', 'l', 'm', 'n', 'o']], [['p', 'q', 'r', 's', 't', 'u'], ['v', 'w', 'x', 'y', 'z', 'aa', 'bb'], ['cc', 'dd', 'ee', 'ff', 'gg', 'hh', 'ii', 'jj'], ['kk', 'll', 'mm', 'nn', 'oo', 'pp', 'qq', 'rr', 'ss']]] AS arr)[number], arr[number][number], arr[number][number][number] FROM system.numbers LIMIT 10;