[clang] [llvm] [llvm] properly guard dump methods in Support lib classes (PR #139938)

[Andrew Rogers via cfe-commits]

andrurogerz wrote:

@hvdijk thank you for the clear repro steps; I was able to reproduce the issue locally and verify that #140574 fixes it. It is a partial revert of only the `ScaledNumber` source changes; the rest of the changes in this PR do not appear to have the same issue. 

https://github.com/llvm/llvm-project/pull/139938