Loads from UInt32Arrays should not result in a double up-convert if it isn't necessary

Loads from UInt32Arrays should not result in a double up-convert if it isn't necessary
https://bugs.webkit.org/show_bug.cgi?id=80979
<rdar://problem/11036848>

Reviewed by Oliver Hunt.

Also improved DFG IR dumping to include type information in a somewhat more
intuitive way.

* bytecode/PredictedType.cpp:
(JSC::predictionToAbbreviatedString):
(JSC):
* bytecode/PredictedType.h:
(JSC):
* dfg/DFGAbstractState.cpp:
(JSC::DFG::AbstractState::execute):
* dfg/DFGGraph.cpp:
(JSC::DFG::Graph::dump):
* dfg/DFGPredictionPropagationPhase.cpp:
(JSC::DFG::PredictionPropagationPhase::propagate):
* dfg/DFGSpeculativeJIT.cpp:
(JSC::DFG::SpeculativeJIT::compileUInt32ToNumber):
(JSC::DFG::SpeculativeJIT::compileGetByValOnIntTypedArray):
* dfg/DFGSpeculativeJIT.h:
(JSC::DFG::SpeculativeJIT::forwardSpeculationCheck):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@110631 268f45cc-cd09-0410-ab3c-d52691b4dbfc