Generic/JumbledIncrementer: improve test coverage

This commit adds tests for:
- for alternative syntax
- for loops missing one or more condition parts
- sniff bails early when it encounters a parse error (missing for body
  and inner for loop missing opening parenthesis
- for loops with more than one incrementer
- for loops with decrementers

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

@@ -22,4 +22,62 @@ for ($i = 0; $i < 20; $i++) {
 
         }
     }
-}
+}
+
+for (; $i < 10; $i++) {
+    for ($j = 0;; $j++) {
+        if ($j > 5) {
+            break;
+        }
+        for (;; $k++) {
+            if ($k > 5) {
+                break;
+            }
+        }
+    }
+}
+
+for (; $i < 10; $i++) {
+    for ($j = 0;; $i++) {
+        if ($j > 5) {
+            break;
+        }
+        for (;; $i++) {
+            if ($k > 5) {
+                break;
+            }
+        }
+    }
+}
+
+for ($i = 0; $i < 20; $i++) :
+    for ($j = 0; $j < 5; $j += 2) :
+    endfor;
+endfor;
+
+for ($i = 0; $i < 20; $i++) :
+    for ($j = 0; $j < 5; $i += 2) :
+    endfor;
+endfor;
+
+// Sniff bails early when there is no incrementor in the outer for loop.
+for ($i = 0; $i < 10;) {
+    ++$i;
+    for ($j = 0; $j < 5; $i++) {}
+}
+
+for ($i = 1, $j = 0; $i <= 10; $i++, $j++) {
+    for ($j = 0, $k = 0; $k < 5; $j++, $k++) {}
+}
+
+for ($i = 20; $i > 0; $i--) {
+    for ($j = 5; $j > 0; $j -= 2) {
+        for ($k = 3; $k > 0; $k--) {}
+    }
+}
+
+for ($i = 20; $i > 0; $i--) {
+    for ($j = 5; $j > 0; $i -= 2) {
+        for ($k = 3; $k > 0; $i--) {}
+    }
+}

src/Standards/Generic/Tests/CodeAnalysis/JumbledIncrementerUnitTest.3.inc

@@ -0,0 +1,6 @@
+<?php
+
+// Intentional parse error (missing for body).
+// This should be the only test in this file.
+// Testing that the sniff is *not* triggered.
+for

src/Standards/Generic/Tests/CodeAnalysis/JumbledIncrementerUnitTest.4.inc

@@ -0,0 +1,8 @@
+<?php
+
+// Intentional parse error (inner for loop missing opening parenthesis).
+// This should be the only test in this file.
+// Testing that the sniff is *not* triggered.
+for ($i = 0; $i < 20; $i++) {
+    for
+}

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

@@ -53,6 +53,12 @@ public function getWarningList($testFile='')
                 3  => 2,
                 4  => 1,
                 20 => 1,
+                40 => 2,
+                41 => 1,
+                58 => 1,
+                69 => 1,
+                79 => 2,
+                80 => 1,
             ];
 
         default: