[lcmtypes] Add benchmark

[jwnimmer-tri]

Towards #20761 and therefore towards #17231 and #21868.

The objective here is to have sufficient benchmark coverage that we feel confident switching over the implementation.

Sample output:

----------------------------------------------------------------------------------
Benchmark                              Time             CPU    Allocs   Iterations
----------------------------------------------------------------------------------
LcmFixture/ImageArrayEncode         82.9 us         82.9 us     1.375         7994
LcmFixture/ImageArrayDecode         80.1 us         80.1 us    3.4375         8633
LcmFixture/PandaCommandEncode       29.6 ns         29.6 ns      1.25     24645732
LcmFixture/PandaCommandDecode       3.28 ns         3.28 ns    0.3125    216860095
LcmFixture/PandaStatusEncode        71.0 ns         71.0 ns     1.625      9747702
LcmFixture/PandaStatusDecode        3.12 ns         3.12 ns    0.6875    224399289
LcmFixture/ViewerDrawEncode         4.84 us         4.84 us   95.3125       144837
LcmFixture/ViewerDrawDecode         3.12 ns         3.12 ns    94.375    224434971

---

This change is 

[jwnimmer-tri]

+@sammy-tri this seems like it might be up your alley for feature review?

[sammy-tri]

Will review.

Reviewable status: LGTM missing from assignee sammy-tri(platform), needs at least two assigned reviewers

[sammy-tri]

Reviewed 3 of 3 files at r1, all commit messages.
Reviewable status: needs at least two assigned reviewers

[jwnimmer-tri]

+@xuchenhan-tri for platform review, please (tomorrow).

[xuchenhan-tri]

Reviewed 3 of 3 files at r1, all commit messages.
Reviewable status: 1 unresolved discussion

---

lcmtypes/benchmarking/benchmark.cc line 78 at r1 (raw file):

      message.position[i].resize(3, 0);
      message.quaternion[i].resize(4, 0);
    }

nit, this seems redundant since the values are already set to zero in the resize above.

Code quote:

    for (int i = 0; i < n; ++i) {
      message.position[i].resize(3, 0);
      message.quaternion[i].resize(4, 0);
    }

[sammy-tri]

Reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: complete! all discussions resolved, LGTM from assignees sammy-tri(platform),xuchenhan-tri(platform)

[xuchenhan-tri]

Reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: complete! all discussions resolved, LGTM from assignees sammy-tri(platform),xuchenhan-tri(platform)