Issue 5052. Analyzer should treat assert as a keyword

tests/language/language.status

Index: tests/language/language.status
diff --git a/tests/language/language.status b/tests/language/language.status
index 13a4f5a97711980c82a7edb96e9f480fa47cd706..9a84151ae7915b94d67f046983653a388fb30e09 100644
--- a/tests/language/language.status
+++ b/tests/language/language.status
@@ -101,6 +101,7 @@ compile_time_constant_checked3_test/05: Fail, OK
 compile_time_constant_checked3_test/06: Fail, OK
 
 [ $compiler == dartc ]
+assert_lexical_scope_test: Fail, OK # test issue 5276
 implicit_this_test/none: Fail # should not warn about allocating SubAbstract2
 metadata_test: Fail
 bad_constructor_test/04: Fail # Constructor name clashes with other member
@@ -192,6 +193,7 @@ prefix9_negative_test : Fail # language change 1031
 prefix10_negative_test : Fail # language change 1031
 prefix11_negative_test : Fail # language change 1031
 private_member3_negative_test: Fail # Runtime only test?  rewrite as multitest
+pseudo_kw_test: Fail, OK # test issue 5276
 pseudo_kw_illegal_test/09: Fail, OK # 'interface' is not a built-in identifier
 pseudo_kw_illegal_test/11: Fail, OK # 'negate' is not a built-in identifier
 pseudo_kw_illegal_test/14: Fail, OK # 'source' is not a built-in identifier