Analyze Command lint cleanup.

The push to dev-4 allows us to cleanup a few more bits:
  * `api_docs` lint message special casing (lint fixed)
  * `allowedIdentifiersPattern` (lint fixed)

packages/flutter_tools/lib/src/commands/analyze.dart

@@ -344,11 +344,10 @@ class AnalyzeCommand extends FlutterCommand {
     ];
 
     RegExp generalPattern = new RegExp(r'^\[(error|warning|hint|lint)\] (.+) \(([^(),]+), line ([0-9]+), col ([0-9]+)\)$');
-    RegExp allowedIdentifiersPattern = new RegExp(r'_?([A-Z]|_+)\b');
     RegExp classesWithOptionalTypeArgumentsPattern = new RegExp(r'\b(GlobalKey|State|ScrollableState|Element|StatelessElement|TypeMatcher)\b');
     RegExp conflictingNamesPattern = new RegExp('^The imported libraries \'([^\']+)\' and \'([^\']+)\' cannot have the same name \'([^\']+)\'\$');
     RegExp missingFilePattern = new RegExp('^Target of URI does not exist: \'([^\')]+)\'\$');
-    RegExp documentAllMembersPattern = new RegExp('^Document all public memm?bers\$');
+    RegExp documentAllMembersPattern = new RegExp('^Document all public members\$');
 
     Set<String> changedFiles = new Set<String>(); // files about which we've complained that they changed
 
@@ -407,9 +406,6 @@ class AnalyzeCommand extends FlutterCommand {
           } else if (sourceLines.first.startsWith('// DO NOT EDIT. This is code generated')) {
             // autogenerated code - TODO(ianh): Fix the intl package resource generator
             shouldIgnore = true;
-          } else if (level == 'lint' && errorMessage == 'Name non-constant identifiers using lowerCamelCase.') {
-            if (allowedIdentifiersPattern.matchAsPrefix(sourceLine, colNumber-1) != null)
-              shouldIgnore = true;
           } else if (level == 'lint' && errorMessage == 'Specify type annotations.') {
             // we want the type annotations on certain classes to be optional.
             // see https://github.com/dart-lang/linter/issues/196