Resolve Fail Test

Variable `$var_id` added by commit:

Title:  Fix #302 - add a way to seal objects with magic properties
SHA:    a083069
Date:   2017-11-17
File:   src/Psalm/Checker/Statements/Expression/AssignmentChecker.php
Line:   682

After removing the `$var_id` variable, all project tests are successful.

src/Psalm/Internal/Analyzer/Statements/Expression/Assignment/InstancePropertyAssignmentAnalyzer.php

@@ -1087,7 +1087,7 @@ private static function analyzeAtomicAssignment(
              * If we have an explicit list of all allowed magic properties on the class, and we're
              * not in that list, fall through
              */
-            if (!$var_id || !$class_storage->hasSealedProperties($codebase->config)) {
+            if (!$class_storage->hasSealedProperties($codebase->config)) {
                 if (!$context->collect_initializations && !$context->collect_mutations) {
                     self::taintProperty(
                         $statements_analyzer,