Update to the latest version of libjpeg-turbo

Bug: b/70203010

From https://github.com/libjpeg-turbo/libjpeg-turbo/commit/c308d434.
This commit fixes a bug in BitmapRegionDecoder, and is the tip of tree.

Rather than using our mirror, just pull in upstream directly. Move our
config files into third_party/libjpeg-turbo, so we can just DEPS to
upstream. These files are unchanged, except jconfig.h, where I added a
comment regarding arithmetic coding.

Add a test image which demonstrates the bug.

Change-Id: I00f8f961f69e407dc31ca6d15c66518aa0acbafd
Reviewed-on: https://skia-review.googlesource.com/81442
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Leon Scroggins <scroggo@google.com>
diff --git a/DEPS b/DEPS
index a1f7c8a..50c6f4f 100644
--- a/DEPS
+++ b/DEPS
@@ -12,7 +12,7 @@
   "third_party/externals/icu"           : "https://chromium.googlesource.com/chromium/deps/icu.git@ec9c1133693148470ffe2e5e53576998e3650c1d",
   "third_party/externals/imgui"         : "https://github.com/ocornut/imgui.git@6384eee34f08cb7eab8d835043e1738e4adcdf75",
   "third_party/externals/jsoncpp"       : "https://chromium.googlesource.com/external/github.com/open-source-parsers/jsoncpp.git@1.0.0",
-  "third_party/externals/libjpeg-turbo" : "https://skia.googlesource.com/third_party/libjpeg-turbo.git@6de58e0d28014caf2fc1370145f22fd6d65f63e3",
+  "third_party/externals/libjpeg-turbo" : "https://github.com/libjpeg-turbo/libjpeg-turbo.git@c308d434160fbc33e3ed1cd59641d095c186501e",
   "third_party/externals/libpng"        : "https://skia.googlesource.com/third_party/libpng.git@v1.6.33",
   "third_party/externals/libwebp"       : "https://chromium.googlesource.com/webm/libwebp.git@v0.6.0",
   "third_party/externals/microhttpd"    : "https://android.googlesource.com/platform/external/libmicrohttpd@748945ec6f1c67b7efc934ab0808e1d32f2fb98d",