[lldb][tests] TestPreferredName.py: Fix for older compilers

This only works as of D145803, where we re-point the
`DW_AT_type` based on existence of `[[clang::preferred_name]]`

Author: Michael137

lldb/test/API/lang/cpp/preferred_name/TestPreferredName.py

@@ -11,6 +11,7 @@
 
 class TestPreferredName(TestBase):
 
+    @skipIf(compiler="clang", compiler_version=['<', '16.0'])
     def test_frame_var(self):
         self.build()
         lldbutil.run_to_source_breakpoint(self, "return", lldb.SBFileSpec("main.cpp"))
@@ -26,6 +27,7 @@ def test_frame_var(self):
         self.expect("frame variable varChar", substrs=["Bar<char>"])
         self.expect("frame variable varFooInt", substrs=["Foo<BarInt>"])
 
+    @skipIf(compiler="clang", compiler_version=['<', '16.0'])
     def test_expr(self):
         self.build()
         lldbutil.run_to_source_breakpoint(self, "return", lldb.SBFileSpec("main.cpp"))