refactor stream output and progress bars (part 1) (#5577)

motivation: continue cleanup work, fixing issues when diagnositics output ay interleave with deelgates writing directly to the output or reportig progress

changes:
* change ToolWorkspaceDelegate to use provided  output and progress handlers instead of wirting to OutputStream directly
* add print and progress handlers to SwiftToolObservabilityHandler, including a serial queue to maange the sequence of outputing to the output stream
* adjust tests to wait on diagnostics when necessary given the queue setup

Author: tomerd

Sources/Build/BuildOperation.swift

@@ -302,7 +302,6 @@ public final class BuildOperation: PackageStructureDelegate, SPMBuildCore.BuildS
             fileSystem: self.fileSystem
         )
 
-
         // Surface any diagnostics from build tool plugins.
         for (target, results) in buildToolPluginInvocationResults {
             // There is one result for each plugin that gets applied to a target.