[llvm] [MCA] Optimize memory consumption in resource pressure view (NFC) (PR #124904)

[Andrea Di Biagio via llvm-commits]

adibiagio wrote:

> NB: I use mca rather in unusual way by providing really big input asm sequences and I don't think there would be any noticeable change for small input files, but I still think it worth fixing.

I also don't think that this will have any significant impact on small input files. 
However, it is still worth improving the memory usage for your particular case.

I am happy for this change to go in once Min's comments have been addressed.
Thanks!

https://github.com/llvm/llvm-project/pull/124904