[PHP] Fix cleanup code handling issues

Fix to call cleanup code in exception situations and not to invoke
the freearg typemap twice in certain situations.

Fixes https://sourceforge.net/p/swig/bugs/1211/

Examples/test-suite/php/exception_memory_leak_runme.php

@@ -0,0 +1,23 @@
+<?php
+
+require "tests.php";
+
+check::functions(array('trigger_internal_swig_exception'));
+check::classes(array('Foo', 'exception_memory_leak'));
+// No new vars
+check::globals(array());
+
+$a = new Foo();
+check::equal(Foo::get_count(), 1, "Should have 1 Foo objects");
+$b = new Foo();
+check::equal(Foo::get_count(), 2, "Should have 2 Foo objects");
+
+// Normal behaviour
+trigger_internal_swig_exception("no problem", $a);
+check::equal(Foo::get_count(), 2, "Should have 2 Foo objects");
+check::equal(Foo::get_freearg_count(), 1, "freearg should have been used once");
+
+// SWIG exception triggered and handled.
+trigger_internal_swig_exception("null", $b);
+check::equal(Foo::get_count(), 2, "Should have 2 Foo objects");
+check::equal(Foo::get_freearg_count(), 2, "freearg should have been used twice");