Tune VideoCodecTestLibvpx.MultiresVP8 thresholds.

After https://webrtc-review.googlesource.com/c/src/+/131141 there are some minor
changes to the encoding performance, hence the updated values.

Bug: none
Change-Id: Ifa661eea15a0d52f4760f4aac9294074faab757f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/131382
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Reviewed-by: Sergey Silkin <ssilkin@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27463}

modules/video_coding/codecs/test/videocodec_test_libvpx.cc

diff --git a/modules/video_coding/codecs/test/videocodec_test_libvpx.cc b/modules/video_coding/codecs/test/videocodec_test_libvpx.cc
index 99f2715..71243e2 100644
--- a/modules/video_coding/codecs/test/videocodec_test_libvpx.cc
+++ b/modules/video_coding/codecs/test/videocodec_test_libvpx.cc
@@ -358,7 +358,7 @@
   std::vector<RateProfile> rate_profiles = {{1500, 30, 0}};
 #if defined(WEBRTC_ARCH_ARM) || defined(WEBRTC_ARCH_ARM64)
   std::vector<RateControlThresholds> rc_thresholds = {
-      {3.5, 1.04, 6, 0.18, 0.14, 0.07, 0, 1}};
+      {4.1, 1.04, 6, 0.18, 0.14, 0.08, 0, 1}};
 #else
   std::vector<RateControlThresholds> rc_thresholds = {
       {5, 1, 5, 1, 0.3, 0.1, 0, 1}};