[perf_skottiewasm_lottieweb] Do 2 loops with 25 points each and then pick 25 from the middle

Doing this will avoid the unreliable frames at the start (setup related) and at the end (teardown related). Also:
* Increase timeouts in lottie-web-perf.js and skottie-wasm-perf.js since we are looping twice now.
* Fix bug where ret code was 0 if puppeteer test failed.

NoTry: true
Bug: skia:9237
Change-Id: I0933ecb87113b40c162712076c38fb7379b352d4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/226836
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Ravi Mistry <rmistry@google.com>
9 files changed