Implemented support for generalized void in analyzer.

pkg/analyzer/lib/src/dart/error/syntactic_errors.dart

Index: pkg/analyzer/lib/src/dart/error/syntactic_errors.dart
diff --git a/pkg/analyzer/lib/src/dart/error/syntactic_errors.dart b/pkg/analyzer/lib/src/dart/error/syntactic_errors.dart
index 35aab58752771151088020853edec4db421d4c8a..1424c62a2ecffc837ae04d1b6cda368002629bce 100644
--- a/pkg/analyzer/lib/src/dart/error/syntactic_errors.dart
+++ b/pkg/analyzer/lib/src/dart/error/syntactic_errors.dart
@@ -982,18 +982,6 @@ class ParserErrorCode extends ErrorCode {
       "Try removing the keyword 'var', or "
       "replacing it with the name of the return type.");
 
-  static const ParserErrorCode VOID_PARAMETER = const ParserErrorCode(
-      'VOID_PARAMETER',
-      "Parameters can't have a type of 'void'.",
-      "Try removing the keyword 'var', or "
-      "replacing it with the name of the type of the parameter.");
-
-  static const ParserErrorCode VOID_VARIABLE = const ParserErrorCode(
-      'VOID_VARIABLE',
-      "Variables can't have a type of 'void'.",
-      "Try removing the keyword 'void', or "
-      "replacing it with the name of the type of the variable.");
-
   /**
    * Initialize a newly created error code to have the given [name]. The message
    * associated with the error will be created from the given [message]