Fix simple RuboCop offenses and update TODO file (#1062)

* Fix Layout/EmptyLineAfterMagicComment offense

* Fix Layout/ExtraSpacing offense

* Fix Layout/ClosingParenthesisIndentation offenses

* Fix Style/MutableConstant offense

* Fix Style/UnneededInterpolation offenses

* Fix Style/RedundantParentheses offenses

* Update TODO config for RuboCop

* Add executable bit to test/test_helper.rb

ref: https://travis-ci.org/Shopify/liquid/jobs/488169512#L578

.rubocop_todo.yml

@@ -1,30 +1,11 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2017-11-22 11:35:55 -0500 using RuboCop version 0.49.1.
+# on 2019-02-03 21:12:39 +0530 using RuboCop version 0.49.1.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 3
-# Cop supports --auto-correct.
-Layout/ClosingParenthesisIndentation:
-  Exclude:
-    - 'test/integration/error_handling_test.rb'
-
-# Offense count: 1
-# Cop supports --auto-correct.
-Layout/EmptyLineAfterMagicComment:
-  Exclude:
-    - 'lib/liquid/version.rb'
-
-# Offense count: 1
-# Cop supports --auto-correct.
-# Configuration parameters: AllowForAlignment, ForceEqualSignAlignment.
-Layout/ExtraSpacing:
-  Exclude:
-    - 'test/integration/parsing_quirks_test.rb'
-
 # Offense count: 5
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle, SupportedStyles.
@@ -51,31 +32,26 @@ Lint/InheritException:
   Exclude:
     - 'lib/liquid/interrupts.rb'
 
-# Offense count: 1
-Lint/ScriptPermission:
-  Exclude:
-    - 'test/test_helper.rb'
-
-# Offense count: 52
+# Offense count: 51
 Metrics/AbcSize:
   Max: 56
 
-# Offense count: 13
+# Offense count: 11
 Metrics/CyclomaticComplexity:
   Max: 12
 
-# Offense count: 620
+# Offense count: 639
 # Configuration parameters: AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, IgnoredPatterns.
 # URISchemes: http, https
 Metrics/LineLength:
   Max: 294
 
-# Offense count: 102
+# Offense count: 108
 # Configuration parameters: CountComments.
 Metrics/MethodLength:
   Max: 37
 
-# Offense count: 9
+# Offense count: 7
 Metrics/PerceivedComplexity:
   Max: 11
 
@@ -143,23 +119,6 @@ Style/GuardClause:
     - 'lib/liquid/variable.rb'
     - 'test/unit/tokenizer_unit_test.rb'
 
-# Offense count: 4
-# Configuration parameters: SupportedStyles.
-# SupportedStyles: snake_case, camelCase
-Style/MethodName:
-  EnforcedStyle: snake_case
-
-# Offense count: 6
-# Cop supports --auto-correct.
-Style/MutableConstant:
-  Exclude:
-    - 'lib/liquid/expression.rb'
-    - 'lib/liquid/lexer.rb'
-    - 'lib/liquid/standardfilters.rb'
-    - 'lib/liquid/tags/if.rb'
-    - 'lib/liquid/variable_lookup.rb'
-    - 'lib/liquid/version.rb'
-
 # Offense count: 1
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle, MinBodyLength, SupportedStyles.
@@ -190,12 +149,6 @@ Style/PercentLiteralDelimiters:
     - 'test/integration/assign_test.rb'
     - 'test/integration/standard_filter_test.rb'
 
-# Offense count: 2
-# Cop supports --auto-correct.
-Style/RedundantParentheses:
-  Exclude:
-    - 'test/unit/condition_unit_test.rb'
-
 # Offense count: 1
 # Cop supports --auto-correct.
 Style/RedundantSelf:
@@ -227,13 +180,6 @@ Style/TernaryParentheses:
     - 'lib/liquid/context.rb'
     - 'lib/liquid/utils.rb'
 
-# Offense count: 4
-# Cop supports --auto-correct.
-Style/UnneededInterpolation:
-  Exclude:
-    - 'lib/liquid/i18n.rb'
-    - 'test/integration/standard_filter_test.rb'
-
 # Offense count: 2
 # Cop supports --auto-correct.
 Style/UnneededPercentQ: