[LLDB][ARM] Remove expected failure from AnonTypedef test

Thanks to ff9efe240c this test
is now passing.

https://lab.llvm.org/buildbot/#/builders/17/builds/26270

lldb/test/API/commands/expression/anonymous-struct/TestCallUserAnonTypedef.py

@@ -14,10 +14,6 @@ from lldbsuite.test import lldbutil
 
 class TestExprLookupAnonStructTypedef(TestBase):
 
-    @expectedFailureAll(
-        oslist=['linux'],
-        archs=['arm'],
-        bugnumber="llvm.org/pr27868")
     def test(self):
         """Test typedeffed untagged struct arguments for function call expressions"""
         self.build()