[lldb] Also disable de-registration of EHFrames in IRExecutionUnit

Summary:
We disabled registration by providing an empty `registerEHFrames`, so we should also provide an empty `deregisterEHFrames`
in case that function relies on `registerEHFrames` being called before. Currently `deregisterEHFrames` is a no-op anyway
as it just iterates over the (empty( list of registered EHFrames and then clear the empty list.

Reviewers: davide, JDevlieghere

Reviewed By: JDevlieghere

Subscribers: JDevlieghere, lldb-commits

Tags: #upstreaming_lldb_s_downstream_patches, #lldb

Differential Revision: https://reviews.llvm.org/D69713