rubocop: fix the Performance/TimesMap cop offenses

It's a new cop introduced by
rubocop/rubocop#2583

.rubocop_todo.yml

@@ -6,12 +6,6 @@
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 4
-Performance/TimesMap:
-  Exclude:
-    - 'benchmarks/payload_truncator.rb'
-    - 'benchmarks/payload_truncator_string_encoding.rb'
-
 # Offense count: 10
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle, SupportedStyles.

benchmarks/payload_truncator.rb

@@ -4,10 +4,10 @@
 # Generates example errors that should be truncated.
 class Payload
   def self.generate
-    5000.times.map do |i|
+    Array.new(5000) do |i|
       { type: "Error#{i}",
         message: 'X' * 300,
-        backtrace: 300.times.map { 'Y' * 300 } }
+        backtrace: Array.new(300) { 'Y' * 300 } }
     end
   end
 end

benchmarks/payload_truncator_string_encoding.rb

@@ -76,7 +76,7 @@ def mixed
       part = MAX / methods.size
 
       methods.each do |method|
-        strings << part.times.map { StringGenerator.__send__(method) }
+        strings << Array.new(part) { StringGenerator.__send__(method) }
       end
 
       strings.flatten
@@ -89,7 +89,7 @@ def best
     private
 
     def generate(&block)
-      MAX.times.map(&block)
+      Array.new(MAX, &block)
     end
   end
 end