Made check blocking execution policy, only blocking (always returning true) on linux

src/System.Management.Automation/engine/SecurityManagerBase.cs

@@ -90,10 +90,12 @@ namespace System.Management.Automation
             // TODO:PSL this is a workaround since the exception below
             // hides the internal issue of what's going on in terms of
             // execution policy.
+#if LINUX            
             if (Platform.IsCore)
             {
                 return;
             }
+#endif
 
 
 #if DEBUG

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

@@ -433,11 +433,12 @@ namespace System.Management.Automation
 
             // There is no signature support on non-Windows platforms (yet), when
             // execution reaches here, we are sure the file is under product folder
+#if LINUX
             if (Platform.IsCore)
             {
                 return true;
             }
-
+#endif
             // Check the file signature
             Signature fileSignature = SignatureHelper.GetSignature(file, null);
             if ((fileSignature != null) && (fileSignature.IsOSBinary))