[lldb] Fix REQUIRES for DWO relative path test

This was "x86-registered-target" which seems to be false in this test
suite despite me having the x86 backend enabled. The other tests use just "x86"
and with that the test passes on my AArch64 machine fine.

Author: DavidSpickett

lldb/test/Shell/SymbolFile/DWARF/dwo-relative-path.s

@@ -1,7 +1,7 @@
 # Test to verify LLDB searches for dwos with relative paths relative to the
 # binary location, not relative to LLDB's launch location.
 
-# REQUIRES: x86-registered-target
+# REQUIRES: x86
 
 # RUN: llvm-mc --filetype=obj --triple x86_64-pc-linux %s -o %t.o
 # RUN: llvm-objcopy --split-dwo=%T/dwo-relative-path.dwo %t.o