fixed the push mode when a big comment occurs before an internal subset,

* parser.c: fixed the push mode when a big comment occurs before
  an internal subset, should close bug #438835
* test/comment6.xml result//comment6.xml*: added a special
  test in the regression suite
Daniel

svn path=/trunk/; revision=3635
diff --git a/result/comment6.xml b/result/comment6.xml
new file mode 100644
index 0000000..3e6074e
--- /dev/null
+++ b/result/comment6.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0"?>
+<!--
+long comment long comment long comment long comment long comment long comment
+long comment long comment long comment long comment long comment long comment
+long comment long comment long comment long comment long comment long comment
+long comment long comment long comment long comment long comment long comment
+long comment long comment long comment long comment long comment long comment
+long comment long comment long comment long comment long comment long comment
+long comment long comment long comment long comment long comment long comment
+-->
+<!DOCTYPE a [
+<!ELEMENT a EMPTY>
+]>
+<a/>