Roll engine 42917704790d..9bfa4f53cdbe (8 commits) (#37755)

git@github.com:flutter/engine.git/compare/42917704790d...9bfa4f53cdbe

git log 42917704790d..9bfa4f53cdbe --no-merges --oneline
2019-08-07 stuartmorgan@google.com Roll buildroot back to an earlier version (flutter/engine#10681)
2019-08-07 stuartmorgan@google.com Roll buildroot to pick up EGL library name fix (flutter/engine#10679)
2019-08-06 chinmaygarde@google.com Remove semi-redundant try-jobs. (flutter/engine#10485)
2019-08-06 chinmaygarde@google.com Allow embedders to control Dart VM lifecycle on engine shutdown. (flutter/engine#10652)
2019-08-06 matthew-carroll@users.noreply.github.com Android embedding refactor pr40 add static engine cache (flutter/engine#10481)
2019-08-06 skia-flutter-autoroll@skia.org Roll fuchsia/sdk/core/linux-amd64 from W6ZtV... to 9sR9P... (flutter/engine#10672)
2019-08-06 bkonyi@google.com Roll src/third_party/dart 574c4a51c6..c262cbd414 (11 commits)
2019-08-06 stuartmorgan@google.com Roll buildroot for ANGLE support (flutter/engine#10667)

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bin/internal/engine.version

-42917704790d29c1c52f371b397fd8bd7b259188
+9bfa4f53cdbec57b0c3badc47bc13da145816c8d