Generic/ForLoopShouldBeWhileLoop: improve test coverage

This commit adds the following groups of tests:

- A few tests that do not trigger the sniff but should help to
protect against regressions in the future. Including tests using the for
loop alternative syntax.
- A test to exercise code in the sniff to bail early if the `for` keyword is
found without a opening parenthesis. This part was not covered before.

Author: rodrigoprimo

src/Standards/Generic/Tests/CodeAnalysis/ForLoopShouldBeWhileLoopUnitTest.1.inc

@@ -10,4 +10,28 @@ for (; $it->valid();) {
 for (;(($it1->valid() && $foo) || (!$it2->value && ($bar || false)));/*Could be ignored*/) {
     $it1->next();
     $it2->next();
-}
+}
+
+for ($i = 0, $j = 10; $i < $j; $i++, $j--) {
+    echo "i: $i, j: $j\n";
+}
+
+for (;;) {
+    if ($i >= 10) {
+        break;
+    }
+    echo $i++;
+}
+
+for ($i = 0; $i < 10; $i++): ?>
+    <p><?php echo $i; ?></p>
+<?php endfor;
+
+for ($i = 0, $len = count($array); $i < $len; $i++):
+    echo $array[$i];
+endfor;
+
+for (; $i < 10;):
+    echo $i;
+    $i++;
+endfor;

src/Standards/Generic/Tests/CodeAnalysis/ForLoopShouldBeWhileLoopUnitTest.2.inc

@@ -0,0 +1,4 @@
+<?php
+
+// Intentional parse error. Testing that the sniff is *not* triggered in this case.
+for

src/Standards/Generic/Tests/CodeAnalysis/ForLoopShouldBeWhileLoopUnitTest.php

@@ -52,6 +52,7 @@ public function getWarningList($testFile='')
             return [
                 6  => 1,
                 10 => 1,
+                34 => 1,
             ];
         default:
             return [];