[llvm] [DAGCombine] Correctly extend the constant RHS in `TargetLowering::SimplifySetCC` (PR #152862)

[via llvm-commits]

asmok-g wrote:

Heads-up: We saw the following tests used to fail on the original commit under `asan`, but after this fix clang crashes when I try to run them:
- llvm/llvm-project/lldb/test/API/commands/expression/call-function/TestCallStdStringFunction.py.arm_gemu.test
- //llvm/llvm-project/lldb/test/API:commands/expression/call-function/TestCallStdStringFunction.py.test
- /llvm/llvm-project/lldb/test/API:lang/cpp/expr-definition-in-dylib/TestExprDefinitionInDylib.py.arm_gemu.test
- //llvm/llvm-project/lldb/test/API:lang/cpp/expr-definition-in-dylib/TestExprDefinitionInDylib.py.test
I'm still not sure if this is due to something in our internal setup at google. Working on a repro but posting the heads-up in the meanwhile. 

https://github.com/llvm/llvm-project/pull/152862