[1] will
(a) rename test files largely,
(b) split out <srcdoc>-related subtests for image requests
into separate test files, and
(c) omit some of the subtests, because they are redundant,
or due to mismatches between how tests are executed
before and after [1].

It is hard to track the mixture of (a), (b) and (c),
especially to see whether there are regressions by [1].

To remove the effect of (c) to some extent,
this CL skips some <srcdoc>-related tests (before [1]).
Ideally, if we can omit (c) from [1], then we can estimate
the number of passing/failing tests before/after [1]
by simple calculation, making it easier to check whether
[1] causes regressions.

The skipped tests have similar (non-skipped) tests so I expect
this CL doesn't substantially reduce test coverage.

[1] https://chromium-review.googlesource.com/c/chromium/src/+/1586548/

Bug: 906850
Change-Id: I4b791ba3a6b7512fea1a2e4debf67f382b966906
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1777094
Commit-Queue: Hiroshige Hayashizaki <[email protected]>
Reviewed-by: Kenichi Ishibashi <[email protected]>
Reviewed-by: Hiroki Nakagawa <[email protected]>
Reviewed-by: Mike West <[email protected]>
Cr-Commit-Position: refs/heads/master@{#692734}