test-http2-session-timeout flaky on FreeBSD

[MylesBorins]

This has been showing up a couple times in the v8.5.0-proposal testing

not ok 854 parallel/test-http2-session-timeout
  ---
  duration_ms: 0.957
  severity: fail
  stack: |-
    (node:89251) ExperimentalWarning: The http2 module is an experimental API.
    assert.js:41
      throw new errors.AssertionError({
      ^
    
    AssertionError [ERR_ASSERTION]: function should not have been called
        at Http2Server.mustNotCall (/usr/home/iojs/build/workspace/node-test-commit-freebsd/nodes/freebsd10-64/test/common/index.js:560:12)
        at emitOne (events.js:115:13)
        at Http2Server.emit (events.js:210:7)
        at process.nextTick (internal/http2/core.js:2282:17)
        at _combinedTickCallback (internal/process/next_tick.js:131:7)
        at process._tickCallback (internal/process/next_tick.js:180:9)
  ...
ok 855 

/cc @nodejs/platform-freebsd

[MylesBorins]

Digging into the test it would appear that this is a timout

server.on('timeout', common.mustNotCall());

[BridgeAR]

Ref #15167 (comment)

[Trott]

I am able to reproduce this trivially with:

tools/test.py -j 96 --repeat 192 test/parallel/test-http2-session-timeout.js

(Note that at this time you need to apply the patch from #15300 or back out c8a389e to use the test runner like that.)

[Trott]

This is not FreeBSD-specific. The test is just straight-up not tolerant of concurrency. Removing the freebsd label.

[Trott]

Aside: This test uses the .timeout property of the Http2Server class but that property (and all properties on that class) is undocumented. @nodejs/http2 @nodejs/documentation

[Trott]

Simplest solution is to bump up serverTimeout. Changing it to 1200 (which is exactly 1/100 of the default value) allows me to run 96 simultaneous copies of the test locally reliably. Previously, I was getting errors sometimes with as few as 8 or 16 concurrent tests, and reliably with 32 concurrent tests.

PR coming momentarily.

[Trott]

Fix (or at least mitigation) is in #15328