Merge pull request #8106 from mikedn/magic-div

Move magic division optimization from morph to lowering

diff --cc src/jit/assertionprop.cpp
Simple merge

diff --cc src/jit/codegenxarch.cpp
Simple merge

diff --cc src/jit/compiler.h
Simple merge

diff --cc src/jit/lower.cpp
Simple merge

diff --cc src/jit/lowerxarch.cpp
Simple merge

diff --cc src/jit/morph.cpp
Simple merge

diff --cc src/jit/valuenum.cpp
Simple merge