fourthTier: DFG shouldn't create CheckStructures for array accesses except if the ArrayMode implies an original array access
https://bugs.webkit.org/show_bug.cgi?id=118867

Reviewed by Mark Hahnenberg.

This allows us to kill off a bunch of code in the parser, in fixup, and to simplify
ArrayProfile.

It also makes it easier to ask any array-using node how to create its type check.

Doing this required fixing a bug in LowLevelInterpreter64, where it was storing into
an array profile, thinking that it was storing into a value profile. Reshuffling the
fields in ArrayProfile revealed this.

* bytecode/ArrayProfile.cpp:
(JSC::ArrayProfile::computeUpdatedPrediction):
(JSC::ArrayProfile::briefDescriptionWithoutUpdating):
* bytecode/ArrayProfile.h:
(JSC::ArrayProfile::ArrayProfile):
(ArrayProfile):
* bytecode/CodeBlock.cpp:
(JSC::CodeBlock::updateAllArrayPredictions):
(JSC::CodeBlock::updateAllPredictions):
* bytecode/CodeBlock.h:
(CodeBlock):
(JSC::CodeBlock::updateAllArrayPredictions):
* dfg/DFGArrayMode.h:
(ArrayMode):
* dfg/DFGByteCodeParser.cpp:
(JSC::DFG::ByteCodeParser::getArrayModeConsideringSlowPath):
(JSC::DFG::ByteCodeParser::parseBlock):
* dfg/DFGFixupPhase.cpp:
(JSC::DFG::FixupPhase::fixupNode):
(FixupPhase):
(JSC::DFG::FixupPhase::checkArray):
(JSC::DFG::FixupPhase::blessArrayOperation):
* llint/LowLevelInterpreter64.asm:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153281 268f45cc-cd09-0410-ab3c-d52691b4dbfc