[lld] Fix -ObjC load behavior with LTO for section names with whitespace (#146654)
This is a fix additional to #92162
In some cases, section names contain a whitespace between the segment
name and the actual section name (e.g. `__TEXT, __swift5_proto`). It is
confirmed by source code of the Swift compiler
This fix allows LTO to work correctly with the `-ObjC` flag in that rare
case when only a section with a whitespace in the name is present in the
linked bitcode module, but there are no sections containing
`__TEXT,__swift`
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Co-authored-by: Ураков Александр Сергеевич <a.urakov@tbank.ru>
Co-authored-by: Ellis Hoag <ellis.sparky.hoag@gmail.com>