Implement simple switch statements as nested if/else.

tests/standalone/standalone.status

Index: tests/standalone/standalone.status
diff --git a/tests/standalone/standalone.status b/tests/standalone/standalone.status
index c5c013b54569e5d6aab5c54af9683460c0f4f6eb..5cfaf2ba62f7e2e46220170cc1654cec5ea4180c 100644
--- a/tests/standalone/standalone.status
+++ b/tests/standalone/standalone.status
@@ -178,7 +178,6 @@ io/file_typed_data_test: Crash # Invalid argument(s)
 io/http_bind_test: Crash # (testBindShared(Stri...  cannot handle async/sync*/async* functions
 io/http_cookie_date_test: Crash # Invalid argument(s)
 io/http_headers_test: Crash # (switch (name.length...  Unhandled node
-io/http_parser_test: Crash # (switch (_state){cas...  Unhandled node
 io/http_proxy_test: Crash # Invalid argument(s)
 io/https_bad_certificate_test: Crash # (main()async{var cli...  cannot handle async/sync*/async* functions
 io/issue_22636_test: Crash # (test()async{server=...  cannot handle async/sync*/async* functions
@@ -187,27 +186,16 @@ io/platform_resolved_executable_test/01: Crash # (try {test(tempDir);}finally {t
 io/platform_resolved_executable_test/02: Crash # (try {test(tempDir);}finally {tempDir.deleteSync(recursive:true);}): try/finally
 io/platform_resolved_executable_test/04: Crash # (try {test(tempDir);}finally {tempDir.deleteSync(recursive:true);}): try/finally
 io/platform_resolved_executable_test/05: Crash # (try {test(tempDir);}finally {tempDir.deleteSync(recursive:true);}): try/finally
-io/raw_datagram_socket_test: Crash # (switch (event){case...  Unhandled node
 io/raw_secure_server_closing_test: Crash # Invalid argument(s)
 io/raw_secure_server_socket_test: Crash # Invalid argument(s)
-io/raw_secure_socket_pause_test: Crash # (switch (event){case...  Unhandled node
-io/raw_secure_socket_test: Crash # (switch (event){case...  Unhandled node
-io/raw_server_socket_cancel_test: Crash # (switch (event){case...  Unhandled node
-io/raw_socket_cross_process_test: Crash # (switch (event){case...  Unhandled node
 io/raw_socket_test: Crash # Instance of 'TypeOperator': type check unimplemented for _Nullary.
 io/raw_socket_typed_data_test: Crash # Invalid argument(s)
-io/regress_21160_test: Crash # (switch (event){case...  Unhandled node
-io/secure_client_raw_server_test: Crash # (switch (event){case...  Unhandled node
 io/secure_server_closing_test: Crash # Invalid argument(s)
 io/secure_server_socket_test: Crash # Invalid argument(s)
-io/secure_socket_bad_data_test: Crash # (switch (event){case...  Unhandled node
 io/skipping_dart2js_compilations_test: Crash # (switch (segment){ca...  Unhandled node
 io/socket_bind_test: Crash # (testListenCloseList...  cannot handle async/sync*/async* functions
-io/socket_close_test: Crash # (switch (_mode){case...  Unhandled node
 io/socket_exception_test: Crash # Invalid argument(s)
 io/socket_source_address_test: Crash # (Future testConnect(...  cannot handle async/sync*/async* functions
 io/socket_upgrade_to_secure_test: Crash # Invalid argument(s)
-io/test_extension_fail_test: Crash # (switch (Platform.op...  Unhandled node
-io/test_extension_test: Crash # (switch (Platform.op...  Unhandled node
 io/test_runner_test: Crash # (switch (arguments[0...  Unhandled node
 priority_queue_stress_test: RuntimeError # Cannot read property 'any$1' of undefined