Bug 922094 - part 1 - report proto/iface cache size to about:memory; r=njn

This is just the nsWindowMemoryReporter bits; the actual measurements come later.
Bug 922094 - part 2 - make nsGlobalWindow report its proto/iface cache size, if appropriate; r=bz
Bug 937540 part 9 - Use placement new for LIR instructions, OOL code. r=luke