[llvm-branch-commits] [NFC][SpecialCaseList] Store SectionStr as StringRef (PR #167278)

[Vitaly Buka via llvm-branch-commits]

https://github.com/vitalybuka created https://github.com/llvm/llvm-project/pull/167278

The SectionStr is already copied in addSection, so
there is no need to copy it again in the Section
constructor.