Update libjpeg-turbo to v2.0.90 (2.1 beta1)

Update Chromium's copy of libjpeg-turbo to the latest upstream
release (v2.0.90) and re-apply our local changes documented in
README.chromium.

Cherry-pick two additional changes from upstream to fix bugs found
by fuzzers:
1) https://github.com/libjpeg-turbo/libjpeg-turbo/commit/ccaba5d7894ecfb5a8f11e48d3f86e1f14d5a469
2) https://github.com/libjpeg-turbo/libjpeg-turbo/commit/c7ca521bc85b57d41d3ad4963c13fc0100481084

Significant changes provided by this update:
1) A large performance boost to JPEG encoding due to an improved
   Huffman encoding implementation.
2) The complete removal of Arm Neon assembly code. This allows Arm's
   control-flow integrity security features (Armv8.3-A Pointer
   Authentication and Armv8.5-A Branch Target Identification) to be
   switched on with the appropriate compiler flags.

Bug: 922430
Bug: b/135180511
Bug: 919548, 1145581
Change-Id: I319fcdc55b3fd5b219425c07a4e4a03587f4e06d
diff --git a/jsimd.h b/jsimd.h
index 33851dc..6c20365 100644
--- a/jsimd.h
+++ b/jsimd.h
@@ -4,6 +4,7 @@
  * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
  * Copyright (C) 2011, 2014, D. R. Commander.
  * Copyright (C) 2015-2016, 2018, Matthieu Darbois.
+ * Copyright (C) 2020, Arm Limited.
  *
  * Based on the x86 SIMD extension for IJG JPEG library,
  * Copyright (C) 1999-2006, MIYASAKA Masaru.