[llvm] [llvm][CodeGen] avoid repeated interval calculation in window scheduler (PR #132352)

[Matt Arsenault via llvm-commits]

================
@@ -0,0 +1,103 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc --mtriple=aarch64 %s -O2 -run-pass=pipeliner -o - | FileCheck %s
----------------
arsenm wrote:

```suggestion
# RUN: llc --mtriple=aarch64 %s -run-pass=pipeliner -o - | FileCheck %s
```

-O2 is the default and the -O flag does nothing with -run-pass 

https://github.com/llvm/llvm-project/pull/132352