Suppress RuboCop Performance 1.9's offenses

This commit suppresss new `Performance/BlockGivenWithExplicitBlock` and
`Performance/Sum` offenses.

```console
Offenses:

lib/rubocop/ast/node.rb:225:51: C:
Performance/BlockGivenWithExplicitBlock: Check block argument explicitly
instead of using block_given?.
        return to_enum(__method__, *types) unless block_given?
                                                  ^^^^^^^^^^^^
(snip)

lib/rubocop/ast/node_pattern/lexer.rb:55:36: C: [Corrected]
Performance/Sum: Use sum { ... } instead of map { ... }.sum.
          flag = options.each_char.map { |c| REGEXP_OPTIONS[c] }.sum
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```

lib/rubocop/ast/node.rb

@@ -222,7 +222,7 @@ def node_parts
       # @return [self] if a block is given
       # @return [Enumerator] if no block is given
       def each_ancestor(*types, &block)
-        return to_enum(__method__, *types) unless block_given?
+        return to_enum(__method__, *types) unless block
 
         visit_ancestors(types, &block)
 

lib/rubocop/ast/node/array_node.rb

@@ -19,7 +19,7 @@ class ArrayNode < Node
 
       # @deprecated Use `values.each` (a.k.a. `children.each`)
       def each_value(&block)
-        return to_enum(__method__) unless block_given?
+        return to_enum(__method__) unless block
 
         values.each(&block)
 

lib/rubocop/ast/node/case_match_node.rb

@@ -17,7 +17,7 @@ def keyword
 
       # @deprecated Use `in_pattern_branches.each`
       def each_in_pattern(&block)
-        return in_pattern_branches.to_enum(__method__) unless block_given?
+        return in_pattern_branches.to_enum(__method__) unless block
 
         in_pattern_branches.each(&block)
 

lib/rubocop/ast/node/case_node.rb

@@ -17,7 +17,7 @@ def keyword
 
       # @deprecated Use `when_branches.each`
       def each_when(&block)
-        return when_branches.to_enum(__method__) unless block_given?
+        return when_branches.to_enum(__method__) unless block
 
         when_branches.each(&block)
 

lib/rubocop/ast/node/const_node.rb

@@ -45,7 +45,7 @@ def relative?
       #      s(:const, :Foo), then
       #      s(:const, s(:const, :Foo), :Bar)
       def each_path(&block)
-        return to_enum(__method__) unless block_given?
+        return to_enum(__method__) unless block
 
         descendants = []
         last = self

lib/rubocop/ast/node/hash_node.rb

@@ -57,7 +57,7 @@ def keys
       # @return [self] if a block is given
       # @return [Enumerator] if no block is given
       def each_key(&block)
-        return pairs.map(&:key).to_enum unless block_given?
+        return pairs.map(&:key).to_enum unless block
 
         pairs.map(&:key).each(&block)
 
@@ -81,7 +81,7 @@ def values
       # @return [self] if a block is given
       # @return [Enumerator] if no block is given
       def each_value(&block)
-        return pairs.map(&:value).to_enum unless block_given?
+        return pairs.map(&:value).to_enum unless block
 
         pairs.map(&:value).each(&block)
 

lib/rubocop/ast/node/if_node.rb

@@ -162,7 +162,7 @@ def branches
 
       # @deprecated Use `branches.each`
       def each_branch(&block)
-        return branches.to_enum(__method__) unless block_given?
+        return branches.to_enum(__method__) unless block
 
         branches.each(&block)
       end

lib/rubocop/ast/node/mixin/descendence.rb

@@ -59,7 +59,7 @@ def child_nodes
       # @return [self] if a block is given
       # @return [Enumerator] if no block is given
       def each_descendant(*types, &block)
-        return to_enum(__method__, *types) unless block_given?
+        return to_enum(__method__, *types) unless block
 
         visit_descendants(types, &block)
 
@@ -94,7 +94,7 @@ def descendants
       # @return [self] if a block is given
       # @return [Enumerator] if no block is given
       def each_node(*types, &block)
-        return to_enum(__method__, *types) unless block_given?
+        return to_enum(__method__, *types) unless block
 
         yield self if types.empty? || types.include?(type)
 

lib/rubocop/ast/node/when_node.rb

@@ -15,7 +15,7 @@ def conditions
 
       # @deprecated Use `conditions.each`
       def each_condition(&block)
-        return conditions.to_enum(__method__) unless block_given?
+        return conditions.to_enum(__method__) unless block
 
         conditions.each(&block)
 

lib/rubocop/ast/node_pattern.rb

@@ -103,7 +103,7 @@ def init_with(coder) #:nodoc:
       # Yields its argument and any descendants, depth-first.
       #
       def self.descend(element, &block)
-        return to_enum(__method__, element) unless block_given?
+        return to_enum(__method__, element) unless block
 
         yield element
 

lib/rubocop/ast/node_pattern/lexer.rb

@@ -52,7 +52,7 @@ def emit_comment
         def emit_regexp
           body = ss[1]
           options = ss[2]
-          flag = options.each_char.map { |c| REGEXP_OPTIONS[c] }.sum
+          flag = options.each_char.sum { |c| REGEXP_OPTIONS[c] }
 
           emit(:tREGEXP) { Regexp.new(body, flag) }
         end