[compiler-rt] [scudo] Clean up string handling (PR #86364)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

@cferris1000 This is causing a -Wmissing-designated-field-initializers (treated as error) on: https://lab.llvm.org/buildbot/#/builders/57/builds/33825

https://github.com/llvm/llvm-project/pull/86364