Inspector: Switch between replay and live probe tree outlines on recording loaded/unloaded.

This is accomplished by managing two tree outlines, each with different logic. The
"live" tree outline only shows probes that have been resolved. The "replay" tree outline
shows all probes, even unresolved probes. When a recording is loaded or unloaded, the
probe section's group is swapped between the live and replay versions.
Inspector: Reloads without interleaved probe samples should create a single separator.

This moves the reload listener to the ProbeGroupObject (model) rather
than ProbeGroupDetailsSection (view). Adding an empty row to the data
grid causes it to fade prior samples.
Inspector: Use ProbeSampleObject.batchId to form data rows atomically.
On replay, save markIndex and batchIdDelta for each row.
Inspector: Opening probe details panel requires only a single click
after reload. Renamed some confusing things in DebuggerSidebarPanel.
Inspector: Clicking on a script in the debugger sidebar panel doesn't
open the probes panel unless a probe group has already been viewed.

ProbeGroupObject updates the hitCount any time a new input is seen.
Inspector: simplify some functions in DebuggerSidebarPanel and fix mis-merges.