Run All showing conflicting adapter(s) for .NET Core xunit projects

[MiaomiaoHuangfu]

Steps to reproduce

1. create a xUnit Test (.NET Core) project;

2. click "Test Explorer" window under Test menu;

3. build the projects succeeded;

4. Click "Run All" under Test explorer window

Expected behavior

Test passed with no warning in output window;

Actual behavior

There is warning in output window"Multiple test adapters with the same uri 'executor://xunit/VsTestRunner2' were found. Ignoring adapter 'Xunit.Runner.VisualStudio.TestAdapter.VsTestRunner'. Please uninstall the conflicting adapter(s) to avoid this warning."

Environment

Install d15prerel.26605.02;
Install latest CLI/SDK 2.0. from https://github.com/dotnet/cli/tree/release/2.0.0
Build version of vstest.console: 15.0.26605.02
dotnet --info

.NET Command Line Tools (2.0.0-preview2-006341)

Product Information:
 Version:            2.0.0-preview2-006341
 Commit SHA-1 hash:  19d305783b

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.14393
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\2.0.0-preview2-006341\

Microsoft .NET Core Shared Framework Host

  Version  : 2.0.0-preview2-25402-02
  Build    : 3c440c8947e7776b2c7772bcb98b3bc73e1b9193

[Faizan2304]

This is happening due to same reason as #840 is happening.
Closing it as duplicate.