[lldb] Require x86 backend for a bunch of DWARF tests

By moving them into a folder with a local lit config
requiring x86. All these tests use x86 target triples.

There are two tests that require target-x86_64 because
they run program files (instead of just needing the backend).
Those are moved to the x86 folder also but their REQUIRES are
unchanged.

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D100193