Steps to reproduce

• Create dotnet global tool dotnet new global-tool -n my-tool --command-name go
• dotnet pack --ouput ./
• install dotnet tool install -g my-tool --source ./
• run go

Error in latest SDK (see --version below)
A fatal error was encountered. The library 'hostpolicy.dll' required to execute the application was not found in 'C:\Program Files\dotnet'.

same on macOS
A fatal error was encountered. The library 'libhostpolicy.dylib' required to execute the application was not found in '/usr/local/share/dotnet'.

Environment data

dotnet --info output:

.NET Core SDK (reflecting any global.json):
 Version:   2.1.300-preview2-008530
 Commit:    822ae6d43a

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.17133
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\2.1.300-preview2-008530\

Host (useful for support):
  Version: 2.1.0-preview2-26406-04
  Commit:  6833f3026b