Ruby 2.5 compat

this partially reverts 4480718

Author: amatsuda

lib/simplecov.rb

@@ -347,9 +347,9 @@ def start_coverage_measurement
     end
 
     def start_coverage_with_criteria
-      start_arguments = coverage_criteria.to_h do |criterion|
+      start_arguments = coverage_criteria.map do |criterion|
         [lookup_corresponding_ruby_coverage_name(criterion), true]
-      end
+      end.to_h
 
       start_arguments[:eval] = true if coverage_for_eval_enabled?
 

lib/simplecov/configuration.rb

@@ -344,7 +344,7 @@ def minimum_coverage_by_file(coverage = nil)
     def refuse_coverage_drop(*criteria)
       criteria = coverage_criteria if criteria.empty?
 
-      maximum_coverage_drop(criteria.to_h { |c| [c, 0] })
+      maximum_coverage_drop(criteria.map { |c| [c, 0] }.to_h)
     end
 
     #