Remove Platform.HasExecutionPolicy query

Also change Get-ExecutionPolicy to not throw, but to return
Unrestricted (which is the effect of the actual policy).

src/System.Management.Automation/CoreCLR/CorePsPlatform.cs

@@ -217,12 +217,6 @@ namespace System.Management.Automation
 
         }
 
-        // Linux does not have PowerShell execution policies
-        internal static bool HasExecutionPolicy()
-        {
-            return IsWindows;
-        }
-
         // Linux has a single rooted file system
         internal static bool HasSingleRootFilesystem()
         {

src/System.Management.Automation/security/SecuritySupport.cs

@@ -138,11 +138,9 @@ namespace System.Management.Automation
 
         internal static void SetExecutionPolicy(ExecutionPolicyScope scope, ExecutionPolicy policy, string shellId)
         {
-            if (!Platform.HasExecutionPolicy())
-            {
+#if LINUX
             throw new PlatformNotSupportedException();
-            }
-
+#else
             string executionPolicy = "Restricted";
             string preferenceKey = Utils.GetRegistryConfigurationPath(shellId);
             const string PolicyKeyValueName = "ExecutionPolicy";
@@ -227,6 +225,7 @@ namespace System.Management.Automation
                     break;
                 }
             }
+#endif
         }
 
         // Clean up the parents of a registry key as long as they
@@ -283,11 +282,9 @@ namespace System.Management.Automation
 
         internal static ExecutionPolicy GetExecutionPolicy(string shellId, ExecutionPolicyScope scope)
         {
-            if (!Platform.HasExecutionPolicy())
-            {
-                throw new PlatformNotSupportedException();
-            }
-
+#if LINUX
+            return ExecutionPolicy.Unrestricted;
+#else
             switch (scope)
             {
                 case ExecutionPolicyScope.Process:
@@ -368,6 +365,7 @@ namespace System.Management.Automation
             }
 
             return ExecutionPolicy.Restricted;
+#endif
         }
 
         internal static ExecutionPolicy ParseExecutionPolicy(string policy)

test/powershell/Modules/Microsoft.PowerShell.Security/ExecutionPolicy.Tests.ps1

@@ -1,8 +1,8 @@
 Describe "ExecutionPolicy" {
 
     Context "Check Get-ExecutionPolicy behavior" {
-	It "Should throw PlatformNotSupported when not on Windows" -Skip:$IsWindows {
-	    { Get-ExecutionPolicy } | Should Throw "Operation is not supported on this platform."
+        It "Should unrestricted when not on Windows" -Skip:$IsWindows {
+            Get-ExecutionPolicy | Should Be Unrestricted
         }
 
         It "Should return Microsoft.Powershell.ExecutionPolicy PSObject on Windows" -Skip:($IsLinux -Or $IsOSX) {