Mark APIs shipped.

Merge release/dev16.4 to release/dev16.5

Move macOS_Test to 10.14

Fix sorting for import completion

Fixes #41702

This reverts commit f19214b69c2fbc6aa8431e3aceeb8d805bb99c6f.

This reverts commit 9ef11ce3bcd1ddd60391060962158c2f79215170.

This is the version used in VS 16.5 preview 2 (d16.5 16.5.29721.120)

Make unit testing analyzer a singleton

Change our error handling for GraphQueryManager

Calls to our remote process are wrapped in a "SoftCrashException"
in an attempt to prevent crashes; this exception derives from
OperationCanceledException. This backfires: our GraphQueryManager
does support reporting exceptions to an info bar, so this means anything
that goes wrong in the RPC then gets silently swallowed because we think
it's cancellation instead. Unwrapping makes things better again.

This commit should be reverted when we remove SoftCrashException in
https://github.com/dotnet/roslyn/issues/40476.

Previously, something going wrong would crash the process due to our
fatal error handling in SafeContinueWith. Now we'll just report a
non-fatal error report.

Merge release/dev16.4 to release/dev16.5

Always return available for SyncClassView command

Fix classview sync

The changes made in https://github.com/dotnet/roslyn/pull/41123 fix the
GetHashCode for SubstitutedMethodSymbol for more nullability scenarios,
but end up hashing all generic methods with a non-generic containing
type into the same bucket. This can cause large performance regressions
for the compiler.

This change ensures that substituted symbols which have substitutions
equivalent to their original methods' type parameter continue to be
equal, but substituted methods with different type substitutions are not
considered equal.

Skip flaky Emit test

Part of https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1065328

Switch to UI thread before invoking Workspace.TryApplyChanges

LOC CHECKIN | dotnet/roslyn master | 20200204