Fix build under JDK1.5

http://code.google.com/p/google-caja/issues/detail?id=1017

RichB reports
Hi,

I've got a build error compiling Caja. I checked out the head from svn
and ran Ant and got this. I'm not a Java coder so apologies if this is
a newbie mistake. Could someone please point me in the right
direction.

PluginCompiler:
   [javac] Compiling 28 source files to ...
   [javac] .../src/com/google/caja/plugin/Dom.java:43: method does not override a method from its superclass
   ...



Fixed the compile issue and fixed a number of issues relating to
running tests under 1.5.  Many of these issues resolved around
different iteration order in HashMaps for the two, but I also fixed
issues around 1.5 using a stricter identifier normalization scheme due
to the absence of java.text.normalizer.


Submitted @3464

[Jasvir, 2009-04-30 23:26:31]

LGTM

Thanks for running the tests against 1.5

http://codereview.appspot.com/53059/diff/1014/1017
File tests/com/google/caja/parser/js/ParserTest.java (right):

http://codereview.appspot.com/53059/diff/1014/1017#newcode96
Line 96: runParseTest("parsertest5.js", "parsergolden5.txt");
This tests the slightly larger set of valid characters in identifiers accepted
by Java6 so is ok to disable for Java 1.5.