Remove some recently fixed bugs from the known_issues file

chrome/test/data/reliability/known_crashes.txt

Index: chrome/test/data/reliability/known_crashes.txt
===================================================================
--- chrome/test/data/reliability/known_crashes.txt	(revision 30173)
+++ chrome/test/data/reliability/known_crashes.txt	(working copy)
@@ -100,9 +100,6 @@
 # 20793
 PREFIX : webpluginproxy::setwindowlessbuffer___child_process_logging::setactiveurl
 
-# 20825
-PREFIX : v8::internal::compiler::compile___v8::script::new___v8::script::compile___webcore::v8proxy::compilescript
-
 # 20915
 REGEX : ^base::messagepumpforio::schedulework___ucase_props_trieindex___canonicalize_map$
 PREFIX : base::messagepumpforio::schedulework___propsvectors___propsvectorstrie_index
@@ -139,8 +136,5 @@
 # 23281
 REGEX : tabcontents::washidden___.*___tabcontents::~tabcontents
 
-# bug 23780
-PREFIX : v8::internal::mayaccessprecheck
-
 # bug 25689
 PREFIX : skia::crashforbitmapallocationfailure___skia::platformcanvas::platformcanvas___webpluginproxy::setwindowlessbuffer___webpluginproxy::updategeometry___webplugindelegatestub