PredictableMemoryAccessOptimizations has become unmaintainable as-is.
RedundantLoadElimination does (almost) the same thing as PredictableMemoryAccessOptimizations.
It's not as powerful but good enough because PredictableMemoryAccessOptimizations is actually only needed for promoting integer values for mandatory constant propagation.
And most importantly: RedundantLoadElimination does not insert additional copies which was a big problem in PredictableMemoryAccessOptimizations.
Fixes rdar://142814676
This test has been disabled since 2022.
This re-enables the test in order to have some test coverage of the `-experimental-c-foreign-reference-types` compiler flag.
See `test/Interop/Cxx/foreign-reference/reference-counted.swift` for a very similar test that enables C++ interop.
rdar://101790203
