VB: Don't show "Each" keyword in completion list in nearly complete For loop

Fix standalone determinism tests

Fix F5 for CSharpWinRTTest

Format lock statement with single statement appropriately 

Fixing backward compatibility issues

This project file wasn't including our xunit targets file and hence didn't have an F5 experience.

closes #8078

Standalone tests occur when we delete csc.exe / vbc.exe from the Binaries\Debug directory and run unit tests.  The tests will fall back to the installed version of the binaries inside MSbuild instead.

The determinism tests were not properly quoting the path to csc.exe.  When run from standalone the path contains a space and hence the tests failed.  Properly quoting the tests now.

closes #8340

Ensure that we process symbol declared events for partial symbols for…

Fixes #3748

A regression test has been added for this bug.

Fixes #7900

Format lock statement with embedded statement as a special node

Suppress $ReturnValue in the Locals window

"argument list" -> "parameter list" in options for method declarations

Fixes: #8355

Show assembly name in editor dropdowns for Metadata as Source

Implement IOperationWalker

Bug Fix #7117: Move Options/Imports/Attributes To Top Of File but after banner text

Add regression test for issue #7861

Fix null reference exception when typing a dot after a complete VB Handles clause

Fixes #4946

This is a tweak to ensure that the completion list does not display the "Each" keyword in a For loop that is already recognizable as a For loop (e.g. has an '=' token). For example, this case:

```VB
For | = 1 to 10
Next
```

The reason for this tweak is to avoid a conflict with the VB "For" snippet. If "Each" is recommended in this position, it causes the completion list to be displayed, which steals the TAB key from snippet navigation. VS 2013 did not show "Each" here either for exactly the same reason.

Fix VB Inline Temporary Variable to work properly when identifiers differ by case

Properly handle __arglist argument in OverloadResolution.BetterFunctionMember.

Strengthen emit against overflow of user string heap.

As it was only used for implementing Descendants methods for IOperation,
which is now replaced by OperationWalker.

Add tests for reset REPL from project and send to REPL

Fixes #8119

Flush 'add using' caches when we encounter low memory conditions.

Re-enable Add Using in the Interactive Window

Fixes #8307

Use MyGet V3 API