[lldb] Require x86 for various NativePDB, Breakpad and Minidump tests

These tests fail if you build without the x86 llvm backend.
Either because they use an x86 triple or try to backtrace which
requires some x86 knowledge to see all frames.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D100194

GitOrigin-RevId: f152472af576e77f9b8736dafaffd31fce7b13b0
9 files changed