CL [0] renamed the telemetry_benchmarks suite to perf_v2 for  issue 197092 .

[0] https://gerrit.chromium.org/gerrit/45875

platform_MemoryMonitor was added to the suite by [1] for  issue 371418 .

[1] https://chromium-review.googlesource.com/200262

Eventually most other tests were removed from this suite until just two remained: 
 (1) platform_MemoryMonitor
 (2) telemetry_GpuTests

For a while this suite was still being scheduled in the Chrome OS HW Test lab.
At one point, in fact, there was a special lab pool (chromeperf) created for running these tests, and three builders that used the results: 
  daisy-chrome-perf
  lumpy-chrome-perf
  parrot-chrome-perf

In Nov 2014, the pool was removed and these builders were turned down as discussed in [2] and issue 434765.
[2] https://groups.google.com/a/google.com/d/msg/chromeos-performance/nrjoLjuOnsw/HbwzK0nW-9kJ

However, suite:perf_v2 was still being scheduled nightly and weekly.

In June 2016, it was reported in issue 619041 and [3] that platform_MemoryMonitor was generating a huge number of timeseries.
This led to the decision to de-scheduled suite:perf_v2 [4] after moving its only other test (telemetry_GpuTests) out of suite:perf_v2 [5].
[3] https://groups.google.com/a/google.com/d/msg/chromeos-performance/KmJQsrCdrsA/zUNo23jFAQAJ
[4] https://chromium-review.googlesource.com/#/c/chromiumos/third_party/autotest/+/351460/
[5] https://chromium-review.googlesource.com/243654

However, suite:perf_v2 still exists to this day.
Since the current recommendation is to run all performance tests in the bvt-perbuild suite anyway, let's just remove the suite and any references to it.

Its only remaining test, platform_MemoryMonitor, is currently broken ( issue 791829 ), however, previously it was decided to keep the test in the tree so if we want to run it or change it and/or consider putting it back in the suite (and then monitor), we can do that [6].  Therefore, there is an attempt to fix the test for now [7], but it has not yet been added back to any suite.
[6] https://groups.google.com/a/google.com/d/msg/chromeos-performance/KmJQsrCdrsA/kW6hGJ_mAQAJ
[7] https://chromium-review.googlesource.com/#/c/chromiumos/third_party/autotest/+/798818/