Fix nested references to 'ref' foreach variables.

These "walk around" the array being iterated over, so they're a bit trickier
than other variables to get right.

tests/mini/compile_rawvardeclinfinally.d

@@ -1 +1,8 @@
-void foo() { void delegate()[] bar; try {} finally { foreach (dg; bar) dg(); } }
+void foo() {
+    void delegate()[] bar;
+    try {
+    } finally {
+        foreach (dg; bar)
+            dg();
+    }
+}