Fix function pointer representation

Self assignment in expression trees should error

Add support for un-suppressing diagnostics from error list

All assignments in an expression tree should be an error.  Self
assignment was being flagged as only a warning which lead to later
errors in code generation.  Changed the behavior to warn and error for
self assignment (matches native compiler behavior).

close #3826

New version of analyzers

Remove the error list command handler registration for add and remove suppressions commands in ServicesVisualStudio - these commands have been moved down to the core CodeAnalysis layer.

Missed commits from FixInsertAwait

Remove unnecessary references that we causing warnings on Mono

Update to a new version of the Roslyn Diagnostics analyzer package.

Add analyzer loading support for CoreCLR

Function pointer tests

Fix InsertAwait where LeadingTrivia exists
Fixes #5240

A bit of ReferenceManager refactoring

Fix Roslyn EE to handle function pointers

Add null checks when calling IWpfTextView.TextViewModel...

The Web Tools team reported seeing occasional crashes in DataTips.  Dump analysis pointed to GetDataTipText being called on a WpfTextView that was already closed.  Even if the caller (VS IDE) were to check this, there is a race where some other thread could close the view before GetDataTipText executes.  We need to handle this and return gracefully.

Revisit APIs for accessing script variables

https://msdn.microsoft.com/en-us/library/6a71f45d.aspx

Pointer related expressions are omitted because they could be parsed as bitwise operation when parenthesis removed.

Fix NullReferenceException's in the result provider when consuming
function pointers.

The VS 2015 Update 1 version of
Microsoft.VisualStudio.Debugger.Metadata.dll adds support for functions
pointers on the metadata api layer.  We represent it in the LMR type
system through new api's to detect if a type is a function pointer and,
if so, get the return type and argument types.  Currently, the result
provider crashes because it doesn't know how to handle a pointer type
with a null element type.  This change adds a couple of checks to
disable expansion on function pointers, which avoids the problem.  With
this change, the EE will simply display the memory address of the
function pointer in the value column, with the function pointer type in
the type column.

To avoid taking a dependency on the Update 1 version of
Microsoft.VisualStudio.Debugger.MetadataReader.dll before it ships, we
temporarily shim Type.IsFunctionPointer() via an extension method.  The
extension method exploits the fact that the function pointer case is the
only time we can have a pointer type with a null element type.  Once
Update 1 ships and the project references are updated, we can remove the
shim layer can just call Type.IsFunctionPointer() directly.

Allow CodeFixes to edit closed AdditionalDocuments under global undo …

Rename Test() to TestAssignmentExpression1()

Having something named Test() will cause none of the tests in that type to be run.  Causing tests assemblies to silently run without failures.
Also fixed boolean operator issue that would have been found by tests.