[tests] Fix bogus uses of assertThrows.

[tests] Fix bogus uses of assertThrows.

Some tests passed a string as second argument to assertThrows, expecting it to
be matched against the exception.  However, assertThrows simply ignored these.
(Some other tests actually seem to use that argument as a comment ...)

This CL
- changes assertThrows to fail if the second argument is not a function,
- adds assertThrowsEquals which compares the exception to a given value using
  assertEquals
- fixes some bogus tests that got exposed by this.

R=jarin@chromium.org
BUG=

Committed: https://crrev.com/837900ef24dcfaa94fcd6cb3ae00c69f717f4e21
Cr-Commit-Position: refs/heads/master@{#33159}

[Jarin, 2016-01-04 07:42:08]

lgtm

[neis, 2016-01-07 14:25:36]

The CQ bit was checked by neis@chromium.org

[neis, 2016-01-07 14:25:37]

The patchset sent to the CQ was uploaded after l-g-t-m from jarin@chromium.org
Link to the patchset: https://codereview.chromium.org/1544793002/#ps20001
(title: "Rebase")

[commit-bot: I haz the power, 2016-01-07 14:25:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1544793002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1544793002/20001

[commit-bot: I haz the power, 2016-01-07 14:49:01]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-01-07 14:49:26]

Description was changed from

==========
[tests] Fix bogus uses of assertThrows.

Some tests passed a string as second argument to assertThrows, expecting it to
be matched against the exception.  However, assertThrows simply ignored these.
(Some other tests actually seem to use that argument as a comment ...)

This CL
- changes assertThrows to fail if the second argument is not a function,
- adds assertThrowsEquals which compares the exception to a given value using
  assertEquals
- fixes some bogus tests that got exposed by this.

R=jarin@chromium.org
BUG=
==========

to

==========
[tests] Fix bogus uses of assertThrows.

Some tests passed a string as second argument to assertThrows, expecting it to
be matched against the exception.  However, assertThrows simply ignored these.
(Some other tests actually seem to use that argument as a comment ...)

This CL
- changes assertThrows to fail if the second argument is not a function,
- adds assertThrowsEquals which compares the exception to a given value using
  assertEquals
- fixes some bogus tests that got exposed by this.

R=jarin@chromium.org
BUG=

Committed: https://crrev.com/837900ef24dcfaa94fcd6cb3ae00c69f717f4e21
Cr-Commit-Position: refs/heads/master@{#33159}
==========

[commit-bot: I haz the power, 2016-01-07 14:49:27]

Patchset 2 (id:??) landed as
https://crrev.com/837900ef24dcfaa94fcd6cb3ae00c69f717f4e21
Cr-Commit-Position: refs/heads/master@{#33159}