Rename JSC::UStringImpl::data() to characters(), to match WebCore::StringImpl.

JavaScriptCore: 

* API/JSClassRef.cpp:
(OpaqueJSClassContextData::OpaqueJSClassContextData):
* bytecompiler/BytecodeGenerator.cpp:
(JSC::keyForCharacterSwitch):
* bytecompiler/NodesCodegen.cpp:
(JSC::processClauseList):
* interpreter/Interpreter.cpp:
(JSC::Interpreter::privateExecute):
* jit/JITStubs.cpp:
(JSC::DEFINE_STUB_FUNCTION):
* runtime/ArrayPrototype.cpp:
(JSC::arrayProtoFuncToString):
* runtime/Identifier.cpp:
(JSC::Identifier::equal):
(JSC::Identifier::addSlowCase):
* runtime/JSString.cpp:
(JSC::JSString::resolveRope):
* runtime/UString.cpp:
(JSC::UString::toStrictUInt32):
(JSC::equal):
* runtime/UString.h:
(JSC::UString::data):
* runtime/UStringImpl.h:
(JSC::UStringImpl::characters):
(JSC::UStringImpl::hash):
(JSC::UStringImpl::setHash):

WebCore: 

* bridge/jni/jsc/JavaStringJSC.h:
(JSC::Bindings::JavaStringImpl::uchars):
* platform/text/AtomicString.cpp:
(WebCore::AtomicString::add):
(WebCore::AtomicString::find):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@55833 268f45cc-cd09-0410-ab3c-d52691b4dbfc