Revert of Turn on seamless cubemap by default on Desktop GL for ES3. (patchset #3 id:40001 of https://codereview.chromium.org/1831833006/ )

Reason for revert:
This doesn't work on Mac Intel (most likely a driver bug)

Original issue's description:
> Turn on seamless cubemap by default on Desktop GL for ES3.
>
> BUG=597794
> TEST=deqp/texturefiltering_cube_*
> R=piman@chromium.org
> CQ_INCLUDE_TRYBOTS=tryserver.chromium.win:win_optional_gpu_tests_rel
>
> Committed: https://crrev.com/39a22dc8028987efa3ca24135922841d2d2d387c
> Cr-Commit-Position: refs/heads/master@{#383362}

TBR=piman@chromium.org,piman@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=597794

Review URL: https://codereview.chromium.org/1840553002

Cr-Commit-Position: refs/heads/master@{#383405}

gpu/command_buffer/service/gles2_cmd_decoder.cc

@@ -3018,15 +3018,6 @@ bool GLES2DecoderImpl::Initialize(const scoped_refptr<gfx::GLSurface>& surface,
     glEnable(GL_PROGRAM_POINT_SIZE);
   }
 
-  // ES3 requires seamless cubemap. ES2 does not.
-  // However, when ES2 is implemented on top of DX11, seamless cubemap is
-  // always enabled and there is no way to disable it.
-  // Therefore, it seems OK to also always enable it on top of Desktop GL for
-  // both ES2 and ES3 contexts.
-  if (feature_info_->gl_version_info().IsAtLeastGL(3, 2)) {
-    glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
-  }
-
   has_robustness_extension_ =
       context->HasExtension("GL_ARB_robustness") ||
       context->HasExtension("GL_KHR_robustness") ||

gpu/command_buffer/service/gles2_cmd_decoder_unittest_base.cc

@@ -351,12 +351,6 @@ void GLES2DecoderTestBase::InitDecoderWithCommandLine(
         .RetiresOnSaturation();
   }
 
-  if (group_->feature_info()->gl_version_info().IsAtLeastGL(3, 2)) {
-    EXPECT_CALL(*gl_, Enable(GL_TEXTURE_CUBE_MAP_SEAMLESS))
-        .Times(1)
-        .RetiresOnSaturation();
-  }
-
   static GLint max_viewport_dims[] = {
     kMaxViewportWidth,
     kMaxViewportHeight