[llvm] Merge sourcelocation in CSEMIRBuilder::getDominatingInstrForID. (PR #90922)

[Adrian Prantl via llvm-commits]

================
@@ -0,0 +1,62 @@
+# RUN: llc %s -O0 --start-before=legalizer --stop-after=legalizer -o - | FileCheck %s 
+# CHECK-NOT: %35:_(s32) = G_CONSTANT i32 0, debug-location !71
----------------
adrian-prantl wrote:

Can you comment what this test is testing?

https://github.com/llvm/llvm-project/pull/90922