AVX-512: Remember the position of operand with broadcast or embedded rounding

AVX-512: Remember the position of operand with broadcast or embedded rounding

It was not so straight forward to find the postion of operand that has
a broadcasting, embedded rounding mode or SAE (Suppress All Exceptions)
decorator out from operands types or bytecode.
Remebering the postion of the operand of interest in the parser reduces
the burden that assembler looks through the operands.

Signed-off-by: Jin Kyu Song <jin.kyu.song@intel.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>