[lldb] Remove ELF .zdebug support

clang 14 removed -gz=zlib-gnu support and ld.lld/llvm-objcopy removed zlib-gnu
support recently. Remove lldb support by migrating away from
llvm::object::Decompressor::isCompressedELFSection.
The API has another user llvm-dwp, so it is not removed in this patch.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D129724