DFG JIT - Where arguments passed are integers, speculate this.

DFG JIT - Where arguments passed are integers, speculate this.
https://bugs.webkit.org/show_bug.cgi?id=64630

Reviewed by Sam Weinig.

Presently the DFG JIT is overly aggressively predicting double.
Use a bit of dynamic information, and curtail this a little.

* dfg/DFGGraph.cpp:
(JSC::DFG::Graph::predictArgumentTypes):
    - Check for integer arguments.
* dfg/DFGGraph.h:
    - Function declaration.
* runtime/Executable.cpp:
(JSC::tryDFGCompile):
(JSC::FunctionExecutable::compileForCallInternal):
    - Add call to predictArgumentTypes.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@91115 268f45cc-cd09-0410-ab3c-d52691b4dbfc