1, add explicit value cache in emitting indices calculation;
2, move the indices calculation emitting logics into
ConvertTritonGPUOpToLLVMPatternBase to avoid the redundant build cost by
templates. Refer to the discussion in this thread by @LyricZhao :
https://triton-lang.slack.com/archives/C042VBSQWNS/p1671336755922969