[Backport MB-51063 to 7.1.2] [CBSE] PickRandom: filterByTiming: Dont refetch the load stats again after leastLoad value is calculated

In PickRandom function when we are filtering by scan timings in filterByTiming

...

// compute replica with least load.

sort.Float64s(loadList)

leastLoad := loadList[0]//

// Filter inst based on load

//

for i, instId := range replicas {

    if load, ok := currmeta.loads[common.IndexInstId(instId)]; ok {

        if n, ok := load.getLoad(common.PartitionId(partnId)); ok { 

...

Load stats can change after the computation of the leastLoad and if they change beyond the equivalenceFactor we might endup in not picking any replica to serve the scan

So we should be using the same loadValues that are used to calculate the leastLoad for filtering the replicas.