test: Fix testcase 84

Fix testcase 84 arg_mixed in ubuntu24.04

Signed-off-by: GYUHA LEE <leejune30@chungbuk.ac.kr>

Author: gyuha-wa-vect0r

tests/t084_arg_mixed.py

@@ -47,3 +47,8 @@ def setup(self):
             self.option += '-R "mixed_div@retval/f80" '
             self.option += '-A "mixed_str@arg1/s,fparg1" '
             self.option += '-R "mixed_str@retval/s"'
+
+    def fixup(self, cflags, result):
+        if cflags.find('O1') >= 0 or cflags.find('O2') >= 0 or cflags.find('O3') >= 0:
+            return result.replace('mixed_sub(0x400000, 2048) = 0x3ff800;',
+                                'mixed_sub.specialized.1();')