PERF: Improve performance of where when using an array of values

[kamipo]

This is a smaller alternative of performance improvement, without
refactoring type casting mechanism #39009.

This is relatively a smaller change (but about 40% faster than before),
so I think this could be easier reviewed without discuss about
refactoring type casting mechanism.

This just makes attribute.in(values) less allocation from an array of
casted nodes to one casted array node.

ids = (1..1000).each.map do |n|
  Post.create!.id
end

Benchmark.ips do |x|
  x.report("where with ids") do
    Post.where(id: ids).to_a
  end

  x.report("where with sanitize") do
    Post.where(ActiveRecord::Base.sanitize_sql(["id IN (?)", ids])).to_a
  end

  x.compare!
end

Before:

Warming up --------------------------------------
      where with ids     7.000  i/100ms
 where with sanitize    13.000  i/100ms

Calculating -------------------------------------
      where with ids     70.661  (± 5.7%) i/s -    357.000  in   5.072771s
 where with sanitize    130.993  (± 7.6%) i/s -    663.000  in   5.096085s

Comparison:
 where with sanitize:      131.0 i/s
      where with ids:       70.7 i/s - 1.85x  slower

After:

Warming up --------------------------------------
      where with ids    10.000  i/100ms
 where with sanitize    13.000  i/100ms

Calculating -------------------------------------
      where with ids     98.174  (± 7.1%) i/s -    490.000  in   5.012851s
 where with sanitize    132.289  (± 8.3%) i/s -    663.000  in   5.052728s

Comparison:
 where with sanitize:      132.3 i/s
      where with ids:       98.2 i/s - 1.35x  slower

cc @eileencodes @tenderlove @rafaelfranca

[tenderlove]

Hey! We reverted this so we could merge #39009 in. 🙇

[kamipo]

ah... I'll work based on current master anyway.