Error while running dotnet test --collect:coverage

[harshjain2]

Description

Errors are observed while using --collect:coverage.

Error messages :
1>Done building target "ShowCallOfVSTestTaskWithParameter" in project "UnitTestProject1.csproj".
Done executing task "CallTarget".
Using "Microsoft.TestPlatform.Build.Tasks.VSTestTask" task from assembly "C:\Program Files\dotnet\sdk\2.0.0-preview1-005977\Microsoft.TestPlatform.Build.dll".
Task "Microsoft.TestPlatform.Build.Tasks.VSTestTask"

2> dotnet exec needs a managed .dll or .exe extension. The application specified was 'C:\Program'

Steps to reproduce

Run `dotnet test --collect:coverage

Expected behavior

Test should run with a message Could not find data collector "coverage"

Actual behavior

Error message is logged and test run fails.

Reported by @Alxandr @dnelly here

[codito]

Triaging this for 15.5 since code coverage experience is incomplete without this.