Revert "Reland "Activating AVX2 support by default""

This reverts commit a0ad0bbf8f4b7a20c6efb6950ede2a44205b2b74.

Reason for revert: Speculative revert. I suspect it breaks downstream project

Original change's description:
> Reland "Activating AVX2 support by default"
>
> This is a reland of ad148272b89394978915cb00e1c1be552d908a42
>
> Original change's description:
> > Activating AVX2 support by default
> >
> > This CL activates the newly added AVX2 support by default.
> > The activation is done beneath a kill-switch.
> >
> > Beyond the above, the CL also changes an incorrect DCHECK_GT
> > to a DCHECK_GE.
> >
> > Bug: webrtc:11663
> > Change-Id: I231ccb2f5efabf74cd8190411daa954b2b94a2a0
> > Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/183042
> > Commit-Queue: Per Åhgren <peah@webrtc.org>
> > Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
> > Reviewed-by: Sam Zackrisson <saza@webrtc.org>
> > Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
> > Cr-Commit-Position: refs/heads/master@{#32193}
>
> Bug: webrtc:11663
> Change-Id: Ib41dc1d1c5865f2828699c462939d15d5562df47
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/186262
> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
> Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
> Reviewed-by: Sam Zackrisson <saza@webrtc.org>
> Commit-Queue: Per Åhgren <peah@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#32270}

TBR=mbonadei@webrtc.org,saza@webrtc.org,peah@webrtc.org,kwiberg@webrtc.org

Change-Id: I1305fad8d19ba0bd69a38b9e2959af54f900535d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:11663
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/186304
Reviewed-by: Andrey Logvin <landrey@webrtc.org>
Commit-Queue: Andrey Logvin <landrey@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32273}
diff --git a/modules/audio_processing/audio_processing_unittest.cc b/modules/audio_processing/audio_processing_unittest.cc
index bd18d4d..93ddc97 100644
--- a/modules/audio_processing/audio_processing_unittest.cc
+++ b/modules/audio_processing/audio_processing_unittest.cc
@@ -45,7 +45,6 @@
 #include "rtc_base/system/arch.h"
 #include "rtc_base/task_queue_for_test.h"
 #include "rtc_base/thread.h"
-#include "system_wrappers/include/cpu_features_wrapper.h"
 #include "test/gtest.h"
 #include "test/testsupport/file_utils.h"
 
@@ -349,19 +348,6 @@
   return true;
 }
 
-// Returns the reference file name that matches the current CPU
-// architecture/optimizations.
-std::string GetReferenceFilename() {
-#if defined(WEBRTC_AUDIOPROC_FIXED_PROFILE)
-  return test::ResourcePath("audio_processing/output_data_fixed", "pb");
-#elif defined(WEBRTC_AUDIOPROC_FLOAT_PROFILE)
-  if (GetCPUInfo(kAVX2) != 0) {
-    return test::ResourcePath("audio_processing/output_data_float_avx2", "pb");
-  }
-  return test::ResourcePath("audio_processing/output_data_float", "pb");
-#endif
-}
-
 class ApmTest : public ::testing::Test {
  protected:
   ApmTest();
@@ -429,7 +415,13 @@
 
 ApmTest::ApmTest()
     : output_path_(test::OutputPath()),
-      ref_filename_(GetReferenceFilename()),
+#if defined(WEBRTC_AUDIOPROC_FIXED_PROFILE)
+      ref_filename_(
+          test::ResourcePath("audio_processing/output_data_fixed", "pb")),
+#elif defined(WEBRTC_AUDIOPROC_FLOAT_PROFILE)
+      ref_filename_(
+          test::ResourcePath("audio_processing/output_data_float", "pb")),
+#endif
       output_sample_rate_hz_(0),
       num_output_channels_(0),
       far_file_(NULL),
@@ -1783,7 +1775,7 @@
                   max_output_average - kMaxOutputAverageOffset,
                   kMaxOutputAverageNear);
 #if defined(WEBRTC_AUDIOPROC_FLOAT_PROFILE)
-      const double kFloatNear = 0.002;
+      const double kFloatNear = 0.0005;
       EXPECT_NEAR(test->rms_dbfs_average(), rms_dbfs_average, kFloatNear);
 #endif
     } else {