test262 "negative" test expectations list which exception is thrown. The ES2017
draft specification is very specific about which exception class is thrown
from which path, and V8 works hard to be correct with respect to that spec.
Previously, the test262 test runner would accept any nonzero status code,
such as from a crash, or a FAIL printed out, for a negative test. This
patch makes negative tests check for the right answer using a quick-and-dirty
parsing of the exception printing from d8 to find the exception class.
It invokes d8 in a way to get a status code of 0 from thrown exceptions
so that 'negative' tests aren't actually implemented by negating the output.
Amazingly, this didn't catch any test262 failures, but I verified the extra
checking interactively by changing a negative test to expect a different type
and saw it fail.
BUG=v8:4803
R=machenbach
LOG=Y
Review URL: https://codereview.chromium.org/1766503002
Cr-Commit-Position: refs/heads/master@{#34763}
Many mjsunit tests (as well as the promises-aplus adapter scripts) were
using Object.observe simply for microtask-enqueueing purposes. Replaced
such uses with %EnqueueMicrotask.
Review URL: https://codereview.chromium.org/1246933002
Cr-Commit-Position: refs/heads/master@{#29779}
