fix: bump jpeg quality

[patrickhulce]

related #2217

at some point recently the JPEG library used by chrome has changed so that the quality or file size is now much lower for the same quality setting which is causing smoke tests to fail if they don't use the cached download of Chrome (see https://travis-ci.org/GoogleChrome/lighthouse/jobs/235694158)

this bumps it to give roughly the same output as it does under Chrome stable but we should investigate this more and try to bisect for the cause or track it better

[ebidel]

this bumps it to give roughly the same output as it does under Chrome stable but we should investigate this more and try to bisect for the cause or track it better

File a bug to track that!

[patrickhulce]

@ebidel #2217 is for looking into how it compares to other encoders and automating the tracking of it over time, do we want a separate issue to track down this specific change?

[brendankenny]

LGTM2

re #2217, we can easily install libjpeg-turbo and verify things with SSIM/our eyeballs. I do wonder if there's some build rule we didn't see that swaps in other libraries depending on platform. That would make picking a particular quality number a little harder :)

[patrickhulce]

@brendankenny yeah libjpeg-turbo is one of 3 possibilities I'm not sure under what circumstances the others get triggered would have to do some more digging

https://cs.chromium.org/chromium/src/ui/gfx/codec/jpeg_codec.cc?type=cs&l=47

[patrickhulce]

Culprit looks like https://chromium.googlesource.com/chromium/src/+/86074971b9640dbf59869071b4a18bec51c61424