We can't use `|| true` on Windows, so use `not` instead.
Also, on Windows, program names get downcased because `lit` uses
`os.path.normcase()`, so if we have program names in the output,
make sure the programs are already lower-case.
Fix up the stack overflow test to match the expected output.
Plus fix the macOS build to always build for macOS 26.0 or above.
rdar://101623384
We want to be able to efficiently serialise lists of images, and to do so
it makes most sense to create a separate `ImageMap` type. This also provides
a useful place to put methods to e.g. find an image by address or by build
ID.
rdar://124913332
Alastair Houghton