[llvm] ConstraintSystem: replace data structure with Matrix (PR #98895)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> Looks like Clang crashes with the dry-run version on CTmark https://llvm-compile-time-tracker.com/show_error.php?commit=94bdfca2db58d6e6ff507d073e407acba1046701

Should be fixed now. However, LLVM Compile Time Tracker times out now, and I have no idea how to go about debugging that: https://llvm-compile-time-tracker.com/show_error.php?commit=82ddf545ab4688a550881a7a7404d40fc585143e.

https://github.com/llvm/llvm-project/pull/98895