[flang] [llvm] [Pipeline] Add IPSCCPPass at O3 to fix function specialization phase ordering (PR #201543)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

Compile-time impact: +0.5% https://llvm-compile-time-tracker.com/compare.php?from=f3dcf16115f862f6fa5ea8e520b371f7e57a9c3d&to=240b8a2754ead87f11808d1a177f9c605814a0cb&stat=instructions:u

https://github.com/llvm/llvm-project/pull/201543