Update test platform to 15.3.0-preview-20170609-02.

Fixes:
microsoft/vstest#847

Author: Arun Mahapatra

build/DependencyVersions.props

@@ -9,7 +9,7 @@
     <CLI_NETSDK_Version>2.0.0-preview2-20170602-1</CLI_NETSDK_Version>
     <CLI_NuGet_Version>4.3.0-preview3-4146</CLI_NuGet_Version>
     <CLI_WEBSDK_Version>2.0.0-rel-20170518-512</CLI_WEBSDK_Version>
-    <CLI_TestPlatform_Version>15.3.0-preview-20170601-03</CLI_TestPlatform_Version>
+    <CLI_TestPlatform_Version>15.3.0-preview-20170609-02</CLI_TestPlatform_Version>
     <SharedFrameworkVersion>$(CLI_SharedFrameworkVersion)</SharedFrameworkVersion>
     <SharedHostVersion>$(CLI_SharedFrameworkVersion)</SharedHostVersion>
     <HostFxrVersion>$(CLI_SharedFrameworkVersion)</HostFxrVersion>