fix(LoadUnit): use lqIdx to determine age

[Anzooooo]

1. lqIdx has less bit width.
2. for vectors, the robIdx is the same for multiple flows. Previously, for vectors, we would additionally use uopIdx for judgement. But actually, in theory, we only need to use lqIdx/sqIdx.

Here we change the age judgement for vectors to lqIdx to ensure accurate age judgement. And change the age judgement of scalar to lqIdx as well to reduce the cost.

[XiangShanRobot]

[Generated by IPC robot]
commit: e654aa3

commit	astar	copy_and_run	coremark	gcc	gromacs	lbm	linux	mcf	microbench	milc	namd	povray	wrf	xalancbmk
e654aa3	1.814	0.442	2.639	1.231	2.152	2.141	2.361	0.933	1.406	1.985	3.107	2.558	2.267	3.308

master branch:

commit	astar	copy_and_run	coremark	gcc	gromacs	lbm	linux	mcf	microbench	milc	namd	povray	wrf	xalancbmk
4d393af				1.231	2.152	2.141		0.933		1.985	3.107			3.308
7cc7723		0.442	2.639				2.361		1.407			2.558
398aeef	1.814	0.442	2.639	1.231	2.152	2.141	2.361	0.933	1.403	1.985	3.107	2.558	2.267	3.308
d94fbff	1.814	0.442	2.639	1.231	2.152	2.141	2.361	0.933	1.403	1.985	3.107	2.558	2.267	3.308
3642c22	1.814	0.442	2.639	1.231	2.152	2.141	2.361	0.933	1.403	1.985	3.107	2.558	2.267	3.308