Update Roslyn assemblies used in testing with `CORE_ROOT`

[AaronRobinsonMSFT]

The generated CORE_ROOT for running runtime tests contains very old Roslyn assemblies. I'm not sure how to update these properly but it would helpful to have them track with our ingestion of Roslyn.

...\artifacts\TargetingPack>dir Microsoft.CodeAnalysis*
 Volume in drive E is Source
 Volume Serial Number is XXXX-XXXX

 Directory of ...\artifacts\TargetingPack

02-Dec-15  12:29         4,097,216 Microsoft.CodeAnalysis.CSharp.dll
02-Dec-15  12:29         1,901,232 Microsoft.CodeAnalysis.dll
02-Dec-15  12:29         4,957,896 Microsoft.CodeAnalysis.VisualBasic.dll
               3 File(s)     10,956,344 bytes
               0 Dir(s)  96,453,009,408 bytes free

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Issue Details

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The generated CORE_ROOT for running runtime tests contains very old Roslyn assemblies. I'm not sure how to update these properly but it would helpful to have them track with our ingestion of Roslyn.

...\artifacts\TargetingPack>dir Microsoft.CodeAnalysis*
 Volume in drive E is Source
 Volume Serial Number is XXXX-XXXX

 Directory of ...\artifacts\TargetingPack

02-Dec-15  12:29         4,097,216 Microsoft.CodeAnalysis.CSharp.dll
02-Dec-15  12:29         1,901,232 Microsoft.CodeAnalysis.dll
02-Dec-15  12:29         4,957,896 Microsoft.CodeAnalysis.VisualBasic.dll
               3 File(s)     10,956,344 bytes
               0 Dir(s)  96,453,009,408 bytes free

Author:	AaronRobinsonMSFT
Assignees:	-
Labels:	area-Infrastructure
Milestone:	-

[jkoritzinsky]

The Roslyn assemblies are used in the CscBench test that the JIT team owns. They would know best if it would be worthwhile to update to a modern Roslyn version.