Message 270280 - Python tracker

The simplest perf fix is to first use BUILD_TUPLE instead of BUILD_LIST

timeit 'x=1;(x,x,x)'
0.36 usec per loop

timeit 'x=1;[x,x,x]'
0.425 usec per loop

Introducing a new opcode BUILD_STRING to inline PyTuple_New + PyUnicode_Join to replace BUILD_TUPLE + CALL_FUNCTION should benchmark against BUILD_TUPLE version, not BUILD_LIST + CALL_FUNCTION