Migrated test block 20 to Dart 2.0.

tests/corelib/corelib.status

Index: tests/corelib/corelib.status
diff --git a/tests/corelib/corelib.status b/tests/corelib/corelib.status
index 4f2865dba53e30c0104056b1de6aacff1e451cdb..124d1464dd8592d3eddf197bd83fd735e27b16e7 100644
--- a/tests/corelib/corelib.status
+++ b/tests/corelib/corelib.status
@@ -259,14 +259,6 @@ regexp/ecma-regex-examples_test: Crash
 regexp/extended-characters-more_test: Crash
 regexp/global_test: Crash
 regexp/indexof_test: Crash
-regexp/invalid-range-in-class_test: Crash
-regexp/issue_19193_test: Crash
-regexp/lastindex_test: Crash
-regexp/lookahead_test: Crash
-regexp/multiline_test: Crash
-regexp/negative-special-characters_test: Crash
-regexp/no-extensions_test: Crash
-regexp/non-capturing-groups_test: Crash
 regexp/parentheses_test: Crash
 regexp/pcre-test-4_test: Crash
 regexp/pcre_test: Crash
@@ -413,7 +405,6 @@ regexp/alternative-length-miscalculation_test: Crash
 regexp/alternatives_test: Crash
 regexp/assertion_test: Crash
 regexp/backreferences_test: Crash
-regexp/bol-with-multiline_test: Crash
 regexp/bol_test: Crash
 regexp/captures_test: Crash
 regexp/char-insensitive_test: Crash
@@ -423,14 +414,6 @@ regexp/default_arguments_test: Crash
 regexp/dotstar_test: Crash
 regexp/extended-characters-match_test: Crash
 regexp/find-first-asserted_test: Crash
-regexp/look-ahead_test: Crash
-regexp/loop-capture_test: Crash
-regexp/malformed-escapes_test: Crash
-regexp/many-brackets_test: Crash
-regexp/non-bmp_test: Crash
-regexp/non-capturing-backtracking_test: Crash
-regexp/non-character_test: Crash
-regexp/non-greedy-parentheses_test: Crash
 regexp/norepeat_test: Crash
 regexp/overflow_test: Crash
 regexp/stack-overflow2_test: Crash