CollectSourceInformation awareness to query source information

[AbhitejJohn]

Description

Per this issue the adapter is now aware if it is driven by an IDE/CLI. Querying source information for a test method is only required in IDE scenarios where one can run a test from an editor context for instance. Getting source information from the Test Platforms DIA wrapper is a costly operation and is of no use in CLI scenarios.
Filing this issue to conditionally not query for this information when running from CLI to better performance.

Environment

MSTest.TestFramework: 1.1.13
MSTest.TestAdapter: 1.1.13

[AbhitejJohn]

Here are the perf numbers when running tests if this is fixed:

With DIA	Without DIA
7.44	6.82

This is with 9 test containers each having 10 classes with 100 tests each summing out to 9000 tests.
Net gain in performance: 8.33%
This is on a 16GB RAM, 2 core machine.

Just detailing the setting that enables this from the linked issue: The new test platform would pass in a runsettings similar to the below when running from IDE.

<Runsettings>
   <RunConfiguration>
       <CollectSourceInformation>true</CollectSourceInformation>
   </RunConfiguration>
</Runsettings>

DesignMode would be false when running from CLI. The code here should conditionally create navigation session information only if DesignMode is true.

One can invoke the new TestPlatform's vstest.console from "%programfiles(x86)%\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\Extensions\TestPlatform" when VS 2017 RTM is installed.