Revert "Emit callable expressions as regular function closures for PHP < 7.4"

This reverts commit 30de584.

Author: thekid

src/main/php/lang/ast/emit/CallablesAsClosures.class.php

@@ -8,7 +8,7 @@
  * @see  https://wiki.php.net/rfc#php_70
  */
 class PHP70 extends PHP {
-  use OmitPropertyTypes, OmitConstModifiers, CallablesAsClosures;
+  use OmitPropertyTypes, OmitConstModifiers;
   use RewriteNullCoalesceAssignment, RewriteLambdaExpressions, RewriteMultiCatch, RewriteClassOnObjects, RewriteExplicitOctals;
 
   /** Sets up type => literal mappings */

src/main/php/lang/ast/emit/PHP70.class.php

@@ -8,7 +8,7 @@
  * @see  https://wiki.php.net/rfc#php_71
  */
 class PHP71 extends PHP {
-  use OmitPropertyTypes, CallablesAsClosures;
+  use OmitPropertyTypes;
   use RewriteNullCoalesceAssignment, RewriteLambdaExpressions, RewriteClassOnObjects, RewriteExplicitOctals;
 
   /** Sets up type => literal mappings */

src/main/php/lang/ast/emit/PHP71.class.php

@@ -8,7 +8,7 @@
  * @see  https://wiki.php.net/rfc#php_72
  */
 class PHP72 extends PHP {
-  use OmitPropertyTypes, CallablesAsClosures;
+  use OmitPropertyTypes;
   use RewriteNullCoalesceAssignment, RewriteLambdaExpressions, RewriteClassOnObjects, RewriteExplicitOctals;
 
   /** Sets up type => literal mappings */