[clang-tidy] fix readability-redundant-member-init auto-fix of Function-try-block

Summary: This fixes https://bugs.llvm.org/show_bug.cgi?id=39310

Reviewers: malcolm.parsons, ioeric

Reviewed By: malcolm.parsons

Subscribers: xazax.hun

Tags: #clang-format, #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D74800