Update CoreCLR & Corefx dependencies based on ldd method.

Use a hardcoded list for ubuntu and slight refactoring for cleaner targets
code.

scripts/dotnet-cli-build/Utils/AptDependencyUtility.cs

@@ -0,0 +1,24 @@
+using System;
+using System.IO;
+using System.Collections.Generic;
+using System.Text.RegularExpressions;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.DotNet.Cli.Build.Framework;
+
+namespace Microsoft.DotNet.Cli.Build
+{
+    public class AptDependencyUtility
+    {
+        internal static bool PackageIsInstalled(string packageName)
+        {
+            var result = Command.Create("dpkg", "-s", packageName)
+                .CaptureStdOut()
+                .CaptureStdErr()
+                .QuietBuildReporter()
+                .Execute();
+
+            return result.ExitCode == 0;
+        }
+    }
+}