[lldb][test] TestFrameVarDILGlobalVariableLookup: only XFAIL earlier DWARF versions on macOS

On Linux we would use the manual DWARF index and the failing test assertion (see `c40b6904751da529a0436faf72d5d63d35484689`) would still pass.

Author: Michael137

lldb/test/API/commands/frame/var-dil/basics/GlobalVariableLookup/TestFrameVarDILGlobalVariableLookup.py

@@ -19,7 +19,10 @@ class TestFrameVarDILGlobalVariableLookup(TestBase):
     NO_DEBUG_INFO_TESTCASE = True
 
     @skipIf(macos_version=["<", "15.0"], archs=["arm64", "arm64e"])
-    @expectedFailureAll(dwarf_version=["<", "5"])
+    @expectedFailureAll(
+        dwarf_version=["<", "5"],
+        oslist=[lldbplatformutil.getDarwinOSTriples()],
+    )
     @expectedFailureAll(
         compiler="clang",
         compiler_version=["<", "19.0"],