Revert of Disable failing modules_unittests for UBSan. (patchset #1 id:40001 of https://codereview.webrtc.org/1915813002/ )

Reason for revert:
Fix upstream should've landed in our repository.

Original issue's description:
> Disable failing modules_unittests for UBSan.
>
> BUG=webrtc:5820
> TBR=pbos@webrtc.org
>
> Committed: https://crrev.com/c23bf2e54d922486254cdd7657aafceaa958ce25
> Cr-Commit-Position: refs/heads/master@{#12482}

TBR=kjellander@webrtc.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:5820

Review-Url: https://codereview.webrtc.org/1937153002
Cr-Commit-Position: refs/heads/master@{#12647}
diff --git a/webrtc/modules/audio_coding/neteq/neteq_unittest.cc b/webrtc/modules/audio_coding/neteq/neteq_unittest.cc
index ad7a201..69c3876 100644
--- a/webrtc/modules/audio_coding/neteq/neteq_unittest.cc
+++ b/webrtc/modules/audio_coding/neteq/neteq_unittest.cc
@@ -446,11 +446,10 @@
   *payload_len = 1;  // Only noise level, no spectral parameters.
 }
 
-// Disabled for UBSan: https://bugs.chromium.org/p/webrtc/issues/detail?id=5820
 #if !defined(WEBRTC_IOS) && defined(WEBRTC_NETEQ_UNITTEST_BITEXACT) && \
     (defined(WEBRTC_CODEC_ISAC) || defined(WEBRTC_CODEC_ISACFX)) &&    \
     defined(WEBRTC_CODEC_ILBC) && defined(WEBRTC_CODEC_G722) &&        \
-    !defined(WEBRTC_ARCH_ARM64) && !defined(UNDEFINED_SANITIZER)
+    !defined(WEBRTC_ARCH_ARM64)
 #define MAYBE_TestBitExactness TestBitExactness
 #else
 #define MAYBE_TestBitExactness DISABLED_TestBitExactness
@@ -484,10 +483,9 @@
                    FLAGS_gen_ref);
 }
 
-// Disabled for UBSan: https://bugs.chromium.org/p/webrtc/issues/detail?id=5820
 #if !defined(WEBRTC_IOS) && !defined(WEBRTC_ANDROID) &&             \
     defined(WEBRTC_NETEQ_UNITTEST_BITEXACT) &&                      \
-    defined(WEBRTC_CODEC_OPUS) && !defined(UNDEFINED_SANITIZER)
+    defined(WEBRTC_CODEC_OPUS)
 #define MAYBE_TestOpusBitExactness TestOpusBitExactness
 #else
 #define MAYBE_TestOpusBitExactness DISABLED_TestOpusBitExactness