Checks min and max call by Perfomance/CompareWithBlock cop

[pocke]

Ref: #3500

Problem

SortWithBlock cop checks slow sort method call.
min and max method have same performance problem.
However, the methods is not checked by this cop.

• https://ruby-doc.org/core-2.3.3/Enumerable.html#method-i-max
• https://ruby-doc.org/core-2.3.3/Enumerable.html#method-i-min

Benchmark

require 'benchmark'

array = (1..1000000).map { rand(1000000) }

Benchmark.bm(10) do |b|
  b.report("sort")    { array.sort { |a, b| a.to_s <=> b.to_s } }
  b.report("sort_by") { array.sort_by(&:to_s) }

  b.report("max")    { array.max { |a, b| a.to_s <=> b.to_s } }
  b.report("max_by") { array.max_by(&:to_s) }

  b.report("min")    { array.min { |a, b| a.to_s <=> b.to_s } }
  b.report("min_by") { array.min_by(&:to_s) }
end

$ ruby --version
ruby 2.3.2p217 (2016-11-15 revision 56796) [x86_64-linux]
$ ruby test.rb
                 user     system      total        real
sort         6.660000   0.010000   6.670000 (  6.664807)
sort_by      1.910000   0.010000   1.920000 (  1.928268)
max          0.390000   0.000000   0.390000 (  0.385470)
max_by       0.200000   0.000000   0.200000 (  0.203039)
min          0.290000   0.000000   0.290000 (  0.288846)
min_by       0.210000   0.000000   0.210000 (  0.210002)

Goal

I've added a check for max and min methods by CompareWithBlock cop.

• Rename Perfomance/SortWithBlock to Perfomance/CompareWithBlock
• Add test

---

Before submitting the PR make sure the following are checked:

• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Used the same coding conventions as the rest of the project.
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry to the Changelog if the new code introduces user-observable changes. See changelog entry format.
• All tests are passing.
• The new code doesn't generate RuboCop offenses.
• The PR relates to only one subject with a clear title
  and description in grammatically correct, complete sentences.
• Updated cop documentation with rake generate_cops_documentation (required only when you've added a new cop or changed the configuration/documentation of an existing cop).