Changes

# <s>'''Method Inlining'''</s>## <s>What: Inline methods</s>## <s>Dependencies: Bailouts, either profiling, ICs, or calls out to C++</s>## <s>Work involved:</s>### <s>Some heuristic to determine whether methods should be inlined (this can be totally bogus, but maybe better to start with simple methods).</s>### <s>Changing IonBuilder such that JSScripts bytecode parsing can be "stacked" so inner SSA graph is inlined.</s>### <s>Change M/LSnapshots to be nested, so snapshots in an inner frame all point to the same outer snapshot.</s>### <s>Change snapshot encoding and frame reconstruction to support inlining.</s>## <s>Priority: Medium</s>## <s>Time: 3 weeks</s>## <s>Owner: <b>cdleary</b></s>