Ensure that suppression state for build diagnostics shows up as active instead of <blank>, and build diagnostics are not suppressible from error list, i.e. "Suppress" menu does not show up in the error list.

Fixes VSO [#164642](https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems#_a=edit&id=164642)

Fix for issue 6425: Right click "Suppress" should be enabled even when the error list selection has some suppressed issues

Scenario: User bulk selects diagnostics in the error list for suppression/baselining, which includes at least one suppressable diagnostic, but still doesn't see any context menu item for suppressing the diagnostics.

Cause: Our current logic to show the Suppress/Remove suppresion commands require that all the selected diagnostics are active/suppressed respectively. The design team has decided that we should loosen this check to "require that at least one of the selected diagnostics is active/suppressed respectively - this decision was based on the feedback from few people dogfooding this feature.

Fix: Trivial fix to not account for the irrelevant diagnostics when deciding whether or not to show the command. The implementation of the command already drops all the irrelevant diagnostics.

Testing: Verified that we get the desired context menu visiblity for mixed error list selection and invoking the commands also work as expected.

Fixes #6425

Fix "Suppress Active Issues" for project/solution command to use the diagnostics directly from the diagnostic service, instead of the error list. This has multiple benefits:

1. We don't need to wait for error list to be force updated to start computing the suppressions fix. It can take quite a while for error list to reach to stable state

2. We don't do unneccessary mapping from error list entry to roslyn diagnostic snapshots and also don't need to do any filtering of stale diagnostics.

Add support for adding/removing suppressions for diagnostics with no source location. Additionally,  when the diagnostics being suppressed or unsuppressed are across different languages, instead of showing a preview changes dialog per-language, we now show a single preview changes dialog for the entire changed solution.

This change enables "Remove Suppression(s)" context menu command in the error list to enable bulk selecting suppressed issues and removing the suppressions on them.

1) Add an API to the suppression fix service to create a baseline for a given project/solution
2) Don't show preview changes dialog for baseline operation.

Fix unit test failures and address PR feedback: IDE diagnostic service now reports source suppressed diagnostics. So add an optional flag to the diagnostic analyzer service APIs to control whether or not to return suppressed diagnostics, and update the test framework to thread this flag.

1. Add IVisualStudioDiagnosticListSuppressionStateService to maintain information about the suppression state of specific set of items in the error list. This service will be used by error list context menu command handlers to query available commands and also used by the fix service.

2. Add IVisualStudioSuppressionFixService to allow adding or removing bulk suppressions (in source or suppressions file), optionally filtered to a specific project. This command will be used by all baselining scenarios to compute diagnostics and apply bulk suppressions fix.

3. Add a SuppressionStateEventProcessor to process selection changed events in the error list and update the suppression state service information.