Align Linux TP benchmarks with Windows TP benchmarks

Align Linux TP benchmarks with Windows TP benchmarks

On Windows, we download a set of assemblies that we have uploaded to
MyGet. On Linux, we were building corefx each run to get the benchmarks.
This change updates Linux to pull down the same benchmarks Windows uses,
using curl to grab the nuget package from MyGet.

Note: after this commit, we will have data for fewer assemblies on
Linux, but we will now have the same set for both Windows and Linux.
Some data in Benchview may be affected.

Commit migrated from https://github.com/dotnet/coreclr/commit/e38cf70d87a42aa8d0a9b6bdbf3ef7b657955584