test: move http2-misbehaving-flow-control-paused

[Trott]

At least as currently written,
test-http2-misbehaving-flow-control-paused is sensitive to resource
constraints and has been observed to be unreliable in CI. Move it to
sequential so it is not competing with other tests for resources.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

[Trott]

Example CI failure:

https://ci.nodejs.org/job/node-test-commit-freebsd/17556/nodes=freebsd11-x64/console

03:07:37 not ok 921 parallel/test-http2-misbehaving-flow-control-paused
03:07:37   ---
03:07:37   duration_ms: 0.281
03:07:37   severity: fail
03:07:37   exitcode: 1
03:07:37   stack: |-
03:07:37     (node:14866) ExperimentalWarning: The http2 module is an experimental API.
03:07:37     assert.js:77
03:07:37       throw new AssertionError(obj);
03:07:37       ^
03:07:37     
03:07:37     AssertionError [ERR_ASSERTION]: function should not have been called at /usr/home/iojs/build/workspace/node-test-commit-freebsd/nodes/freebsd11-x64/test/parallel/test-http2-misbehaving-flow-control-paused.js:72
03:07:37         at ServerHttp2Stream.mustNotCall (/usr/home/iojs/build/workspace/node-test-commit-freebsd/nodes/freebsd11-x64/test/common/index.js:540:12)
03:07:37         at ServerHttp2Stream.emit (events.js:187:15)
03:07:37         at endReadableNT (_stream_readable.js:1091:14)
03:07:37         at process._tickCallback (internal/process/next_tick.js:63:19)
03:07:37   ...

[Trott]

Replicating the failure from the command line:

$ tools/test.py -j 96 --repeat 192 test/parallel/test-http2-misbehaving-flow-control-paused.js 
=== release test-http2-misbehaving-flow-control-paused ===                     
Path: parallel/test-http2-misbehaving-flow-control-paused
(node:85322) ExperimentalWarning: The http2 module is an experimental API.
assert.js:77
  throw new AssertionError(obj);
  ^

AssertionError [ERR_ASSERTION]: function should not have been called at /Users/trott/io.js/test/parallel/test-http2-misbehaving-flow-control-paused.js:72
    at ServerHttp2Stream.mustNotCall (/Users/trott/io.js/test/common/index.js:540:12)
    at ServerHttp2Stream.emit (events.js:187:15)
    at endReadableNT (_stream_readable.js:1086:12)
    at process._tickCallback (internal/process/next_tick.js:63:19)
Command: out/Release/node /Users/trott/io.js/test/parallel/test-http2-misbehaving-flow-control-paused.js
[SNIP]

[Trott]

CI: https://ci.nodejs.org/job/node-test-pull-request/14704/

[apapirovski]

@Trott see #20556 which fixes the issue in this test.

[Trott]

@apapirovski Cool! Closing this.