xpcom/xptcall: Implemented XPTC_InvokeByIndex in assembly (YASM) as the original mozilla code is making too many assumptions about how the compiler will compile the code. This already broke with gcc 8.2 and asan (bugref:8019) and now Clang breaks it (bugref:9790) when stack is needed for passing parameters. Code has received minimal testing, the floating point stuff isn't tested as we don't use that (I hope). bugref:9790
