Update regex to Harmony r802921.

Notable changes:
 - Reordered methods to be consistent with Harmony. Although our
   implementations are significantly different, this will make
   it easier to track Javadoc and signature changes.
 - Some unchecked exceptions removed from method signatures
 - Changed StringBuffer use to StringBuilder
 - Changed PatternSyntaxException description field to 'desc' for
   serialization compatibility.

commit deba65caf92e9c5b77b29bcf9dcb26d637af90cb
Merge: b239d4a 457c6cc
Author: Jesse Wilson <jessewilson@google.com>
Date:   Wed Aug 12 09:23:58 2009 -0700

    Merge branch 'regex_802921' into regex_dalvik

    Conflicts:
    	libcore/regex/.classpath
    	libcore/regex/.settings/org.eclipse.jdt.core.prefs
    	libcore/regex/build.xml
    	libcore/regex/src/main/java/java/util/regex/AbstractCharClass.java
    	libcore/regex/src/main/java/java/util/regex/AbstractSet.java
    	libcore/regex/src/main/java/java/util/regex/CIDecomposedCharSet.java
    	libcore/regex/src/main/java/java/util/regex/CharClass.java
    	libcore/regex/src/main/java/java/util/regex/DecomposedCharSet.java
    	libcore/regex/src/main/java/java/util/regex/IntArrHash.java
    	libcore/regex/src/main/java/java/util/regex/JointSet.java
    	libcore/regex/src/main/java/java/util/regex/Lexer.java
    	libcore/regex/src/main/java/java/util/regex/MatchResult.java
    	libcore/regex/src/main/java/java/util/regex/Matcher.java
    	libcore/regex/src/main/java/java/util/regex/Pattern.java
    	libcore/regex/src/main/java/java/util/regex/PatternSyntaxException.java
    	libcore/regex/src/main/java/java/util/regex/SequenceSet.java
    	libcore/regex/src/main/java/java/util/regex/UCIDecomposedCharSet.java
    	libcore/regex/src/main/java/java/util/regex/UCISequenceSet.java
    	libcore/regex/src/main/java/org/apache/harmony/regex/internal/nls/messages.properties
    	libcore/regex/src/test/java/org/apache/harmony/tests/java/util/regex/Matcher2Test.java
    	libcore/regex/src/test/java/org/apache/harmony/tests/java/util/regex/MatcherTest.java
    	libcore/regex/src/test/java/org/apache/harmony/tests/java/util/regex/ModeTest.java
    	libcore/regex/src/test/java/org/apache/harmony/tests/java/util/regex/Pattern2Test.java
    	libcore/regex/src/test/java/org/apache/harmony/tests/java/util/regex/PatternErrorTest.java
    	libcore/regex/src/test/java/org/apache/harmony/tests/java/util/regex/PatternSyntaxExceptionTest.java
    	libcore/regex/src/test/java/org/apache/harmony/tests/java/util/regex/PatternTest.java
    	libcore/regex/src/test/java/org/apache/harmony/tests/java/util/regex/ReplaceTest.java
    	libcore/regex/src/test/java/org/apache/harmony/tests/java/util/regex/SplitTest.java

commit b239d4a17905f9e0b609eeaa12de9dfba433c44a
Author: Jesse Wilson <jessewilson@google.com>
Date:   Wed Aug 12 08:37:21 2009 -0700

    Dalvik Regex

commit 457c6cca0629f20b118cd128353439763e40fe9e
Author: Jesse Wilson <jessewilson@google.com>
Date:   Wed Aug 12 08:36:40 2009 -0700

    Regex 802921

commit 51f4e67d71a8f92d8efa073fab32c540f6015594
Author: Jesse Wilson <jessewilson@google.com>
Date:   Wed Aug 12 08:34:57 2009 -0700

    Regex 527399
4 files changed