Roll Flutter Engine from 2b21a3125ca2 to 83092c04c105 (20 revisions) (#113847)

* e27e1964f Add touch-input-test to test_suites.yaml (flutter/engine#36900)

* b923707a3 [Impeller] remove solid stroke contents and allow strokes/vertices to use color sources (flutter/engine#36896)

* 85e4fa84d Roll Dart SDK from e06db8e1b620 to 1d418b40d8bd (1 revision) (flutter/engine#36902)

* 0b57b1cab Roll buildroot to a680bb1c63e6ae. (flutter/engine#36901)

* f1634aa30 Roll Fuchsia Mac SDK from IdQEnRNQNY7ZrLZ04... to jB4jUAxe89I2A-yqv... (flutter/engine#36904)

* f24ea1a04 Roll Fuchsia Linux SDK from g6-kU8so3PDiR1106... to mdl-0MUwR6uuQdKIm... (flutter/engine#36905)

* 04fa86e1b Added integration test for platform channels on windows. (flutter/engine#36853)

* 1dbf3ff76 Convert the executable directory path to UTF-8 on Windows (flutter/engine#36908)

* c3d4fc953 Roll Dart SDK from 1d418b40d8bd to f1d4c7c808bd (2 revisions) (flutter/engine#36913)

* 51b66c968 [Web] Synthesize key events for shift key on pointer events. (flutter/engine#36724)

* 584fffb67 Roll Fuchsia Mac SDK from jB4jUAxe89I2A-yqv... to fcFu9Z2KJH6oQvHnG... (flutter/engine#36919)

* 4369421b8 Roll Fuchsia Linux SDK from mdl-0MUwR6uuQdKIm... to NqPnoRHl3WYqH3SrC... (flutter/engine#36920)

* d6d38abb2 [Impeller] fix null geometry (flutter/engine#36922)

* d7f987ee3 [Impeller] Eliminate unused shader output (flutter/engine#36923)

* c255470e7 Roll Dart SDK from f1d4c7c808bd to eafe0119c9f5 (2 revisions) (flutter/engine#36925)

* 224a3def0 Restore support for building the web SDK without a prebuilt Dart SDK (flutter/engine#36926)

* c7c21e56f Re-landing Robolectric 4.8.1 (flutter/engine#34272)

* ab9802379 Roll libtess2 to 725e5e08ec8751477565f1d603fd7eb9058c277c (flutter/engine#36928)

* 95e937a44 Revert "Roll libtess2 to 725e5e08ec8751477565f1d603fd7eb9058c277c (#36928)" (flutter/engine#36932)

* 83092c04c Revert Dart SDK to 2.19.0-324.0.dev (flutter/engine#36930)

bin/internal/engine.version

-2b21a3125ca25409df0796e900ecc2d0c359e56c
+83092c04c10532b0aa599b4205e36b00a36f59e7

bin/internal/fuchsia-linux.version

-g6-kU8so3PDiR1106nnAkr35Kpk4MBV5gZ6vFVIbNgkC
+NqPnoRHl3WYqH3SrC-klcyyoJSPBDSZFYsl0Bas04c0C

bin/internal/fuchsia-mac.version

-IdQEnRNQNY7ZrLZ04rRZdQ4Z6YdBYyglbOcrJMNYVeAC
+fcFu9Z2KJH6oQvHnGwRsngQjHowI9mBvGX6akXTduzEC