Remove DDC custom error list now that strong mode analyzer handles it

tool/sdk_expected_errors.txt

Index: tool/sdk_expected_errors.txt
diff --git a/tool/sdk_expected_errors.txt b/tool/sdk_expected_errors.txt
index 56cdd9941f5f8b0db50ece156ea1967453053b73..eeca8ed9b5e1dc738bd2af5de214e8a991a0ecf6 100644
--- a/tool/sdk_expected_errors.txt
+++ b/tool/sdk_expected_errors.txt
@@ -14,16 +14,12 @@
 [error] Invalid override. The type of SpeechGrammarList.[]= ((int, SpeechGrammar) → void) is not a subtype of JSMutableIndexable.[]= ((int, dynamic) → dynamic). (dart:html, line 30409, col 3)
 [error] Invalid override. The type of TextTrackList.[]= ((int, TextTrack) → void) is not a subtype of JSMutableIndexable.[]= ((int, dynamic) → dynamic). (dart:html, line 32568, col 3)
 [error] Invalid override. The type of TouchList.[]= ((int, Touch) → void) is not a subtype of JSMutableIndexable.[]= ((int, dynamic) → dynamic). (dart:html, line 32903, col 3)
-[error] The return type '_ElementEventStreamImpl<Event>' is not a 'ElementStream<BeforeUnloadEvent>', as defined by the method 'forElement'. (dart:html, line 36587, col 12)
-[error] The return type '_ElementListEventStreamImpl<Event>' is not a 'ElementStream<BeforeUnloadEvent>', as defined by the method '_forElementList'. (dart:html, line 36592, col 12)
 [error] Invalid override. The type of _CssRuleList.[]= ((int, CssRule) → void) is not a subtype of JSMutableIndexable.[]= ((int, dynamic) → dynamic). (dart:html, line 37674, col 3)
 [error] Invalid override. The type of _GamepadList.[]= ((int, Gamepad) → void) is not a subtype of JSMutableIndexable.[]= ((int, dynamic) → dynamic). (dart:html, line 37928, col 3)
 [error] Invalid override. The type of _NamedNodeMap.[]= ((int, Node) → void) is not a subtype of JSMutableIndexable.[]= ((int, dynamic) → dynamic). (dart:html, line 38135, col 3)
 [error] Invalid override. The type of _SpeechRecognitionResultList.[]= ((int, SpeechRecognitionResult) → void) is not a subtype of JSMutableIndexable.[]= ((int, dynamic) → dynamic). (dart:html, line 38351, col 3)
 [error] Invalid override. The type of _StyleSheetList.[]= ((int, StyleSheet) → void) is not a subtype of JSMutableIndexable.[]= ((int, dynamic) → dynamic). (dart:html, line 38415, col 3)
-[error] The return type '_ElementListEventStreamImpl<Event>' is not a 'ElementStream<T>', as defined by the method '_forElementList'. (dart:html, line 39934, col 12)
 [error] Invalid override. The type of _EventStreamSubscription.asFuture (([dynamic]) → Future<dynamic>) is not a subtype of StreamSubscription<T>.asFuture (<E>([E]) → Future<E>). (dart:html, line 40152, col 3)
-[error] The return type '_WrappedIterator<Node>' is not a 'Iterator<E>', as defined by the method 'iterator'. (dart:html, line 42530, col 31)
 [error] The part was not supplied as an input to the compiler. (dart:html_common/conversions.dart, line 1, col 1)
 [error] The part was not supplied as an input to the compiler. (dart:html_common/conversions_dart2js.dart, line 1, col 1)
 [error] The part was not supplied as an input to the compiler. (dart:html_common/css_class_set.dart, line 1, col 1)
@@ -145,8 +141,6 @@
 [warning] Unsound implicit cast from dynamic to Rectangle<num> (dart:html, line 37634, col 14)
 [warning] Unsound implicit cast from (T) → void to (Event) → dynamic (dart:html, line 40090, col 67)
 [warning] Unsound implicit cast from (T) → void to (Event) → dynamic (dart:html, line 40112, col 45)
-[warning] Unsound implicit cast from From to To (dart:html, line 42593, col 70)
-[warning] Unsound implicit cast from dynamic to To (dart:indexed_db, line 1205, col 37)
 [warning] Unsound implicit cast from num to T (dart:math/rectangle.dart, line 151, col 22)
 [warning] Unsound implicit cast from num to T (dart:math/rectangle.dart, line 152, col 23)
 [warning] Unsound implicit cast from num to T (dart:math/rectangle.dart, line 275, col 10)