Produce a compile-time error if there's no main method.

tests/language/language_kernel.status

Index: tests/language/language_kernel.status
diff --git a/tests/language/language_kernel.status b/tests/language/language_kernel.status
index 2b0ffeb27fc2ce7c8ca08b775000c4d69074e438..f62eafb69c7657abdacd14407f81cbd5a44ba457 100644
--- a/tests/language/language_kernel.status
+++ b/tests/language/language_kernel.status
@@ -121,9 +121,8 @@ enum_syntax_test/06: MissingCompileTimeError
 enum_syntax_test/21: MissingCompileTimeError
 enum_syntax_test/30: MissingCompileTimeError
 evaluation_redirecting_constructor_test: RuntimeError
-export_ambiguous_main_negative_test: Crash
-export_double_same_main_test: Crash
-export_main_test: Crash
+export_double_same_main_test: CompileTimeError
+export_main_test: CompileTimeError
 export_private_test/01: MissingCompileTimeError
 external_test/11: MissingCompileTimeError
 external_test/12: MissingCompileTimeError
@@ -214,7 +213,6 @@ library_ambiguous_test/04: MissingRuntimeError
 library_env_test/has_html_support: RuntimeError
 library_env_test/has_no_io_support: RuntimeError
 list_literal4_test: RuntimeError
-main_not_a_function_test/01: Crash
 malformed2_test/00: RuntimeError
 malformed_inheritance_test/09: MissingCompileTimeError
 malformed_inheritance_test/10: MissingCompileTimeError
@@ -271,7 +269,6 @@ named_parameters_aggregated_test/03: MissingCompileTimeError
 named_parameters_aggregated_test/04: MissingCompileTimeError
 named_parameters_default_eq_test/01: MissingCompileTimeError
 named_parameters_default_eq_test/02: MissingCompileTimeError
-no_main_test/01: Crash
 not_enough_positional_arguments_test/02: MissingRuntimeError  # Dartk Issue 28301
 not_enough_positional_arguments_test/05: MissingRuntimeError  # Dartk Issue 28301
 on_catch_malformed_type_test: RuntimeError