Fix decoding of the deoptimization info when constructing a stack trace.
Fix stack trace for checked mode exceptions from optimized code.
BUG=dart:8058
TEST=runtime/tests/vm/dart/optimized_stacktrace_test.dart,
tests/language/stack_overflow_stacktrace_test.dart
Review URL: https://codereview.chromium.org//12049039
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@17755 260f80e4-7a28-3924-810f-c04153c831b5
fschneider@google.com