[lldb][Test] Prevent generating DW_AT_location for unused argument

[Michael137]

Summary

This test simply checks whether we can print an optimized
function argument. With recent changes to Clang the assumption
that we don't generate a DW_AT_location attribute for the
unused funciton parameter breaks.

This patch tries harder to get Clang to drop the location
from DWARF by making it generate an undef for unused1.
Drop the check for unused2 since it adds no benefit.

[Michael137]

• clang-format

lldb/test/API/functionalities/unused-inlined-parameters/TestUnusedInlinedParameters.py

class TestUnusedInlinedParameters(TestBase):
     def test_unused_inlined_parameters(self):
         self.build()
         lldbutil.run_to_source_breakpoint(self, "// break here", lldb.SBFileSpec("main.c"))
 
         # For the unused parameters, only check the types.
         self.assertIn("(void *) unused1 = <no location, value may have been optimized out>",
                       lldbutil.get_description(self.frame().FindVariable("unused1")))
         self.assertEqual(42, self.frame().FindVariable("used").GetValueAsUnsigned())
-        self.assertIn("(int) unused2 = <no location, value may have been optimized out>",
-                      lldbutil.get_description(self.frame().FindVariable("unused2")))

lldb/test/API/functionalities/unused-inlined-parameters/main.c

 #include <stdio.h>
 
 __attribute__((optnone)) __attribute__((nodebug)) void use(int used) {}
 
-__attribute__((always_inline)) void f(void *unused1, int used, int unused2) {
+__attribute__((always_inline)) void f(void *unused1, int used) {
   use(used); // break here
 }
 
 int main(int argc, char **argv) {
-  f(argv, 42, 1);
+  char *undefined;
+  f(undefined, 42);
   return 0;
-}
+}