https://bugs.webkit.org/show_bug.cgi?id=115942

Reviewed by Oliver Hunt.

Added two obvious nodes: Jump and ForceOSRExit. We already had everything we needed
to support them.

Adding these increases our coverage a fair bit, and revealed a bug: LLVM's full
instruction selector currently appears to mishandle doubles in constant pools (or
just constant pools in general) with the small code model in the MCJIT. But switching
to FastISel "fixes" it. That's what this patch does, for now. This will probably
actually be permanent; the FastISel does pretty much everything we would ever want,
at least in the foreseeable future.

* ftl/FTLCapabilities.cpp:
(JSC::FTL::canCompile):
(FTL):
* ftl/FTLCompile.cpp:
(JSC::FTL::compile):
* ftl/FTLLowerDFGToLLVM.cpp:
(JSC::FTL::LowerDFGToLLVM::compileBlock):
(JSC::FTL::LowerDFGToLLVM::compileNode):
(JSC::FTL::LowerDFGToLLVM::compileJSConstant):
(LowerDFGToLLVM):
(JSC::FTL::LowerDFGToLLVM::compileJump):
(JSC::FTL::LowerDFGToLLVM::compileReturn):
(JSC::FTL::LowerDFGToLLVM::compileForceOSRExit):
* runtime/Options.h:
(JSC):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153156 268f45cc-cd09-0410-ab3c-d52691b4dbfc