Roll SwiftShader 20eea3c..a9969b2

https://swiftshader.googlesource.com/SwiftShader.git/+log/20eea3c..a9969b2

BUG=chromium:854817

TEST=bots

CQ_INCLUDE_TRYBOTS=luci.chromium.try:win_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_chromium_cfi_rel_ng;luci.chromium.try:android_optional_gpu_tests_rel

Change-Id: I13d0fab6a29ba96f13f0e74c07b011db36abbeed
Reviewed-on: https://chromium-review.googlesource.com/1112047Reviewed-by: Alexis Hétu <sugoi@chromium.org>
Commit-Queue: Nicolas Capens <capn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569696}

DEPS

@@ -125,7 +125,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.
-  'swiftshader_revision': '20eea3cd3b2d64e1b8f9811824cb41cacd09389c',
+  'swiftshader_revision': 'a9969b2ab8c30abfd05f4a12c254ddc071e5ba86',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.