Tweak reduce perf point names

Summary:
Tweak reduce phase perf point names so they are clear and aligned with other perf naming for example:
https://www.internalfb.com/code/fbsource/[3c28078fb10c]/fbandroid/libraries/components/litho-core/src/main/java/com/facebook/litho/Layout.kt?lines=66%2C73

Reviewed By: pentiumao

Differential Revision: D52871457

fbshipit-source-id: c2aed48259ea9dcf961aa49454b59fa9eb3037ad

litho-core/src/main/java/com/facebook/litho/LayoutTreeFuture.kt

@@ -173,10 +173,10 @@ class LayoutTreeFuture(
                 result = root)
           }
 
-          perfEvent?.markerPoint("start_collect_results")
+          perfEvent?.markerPoint("start_reduce")
           val layoutState =
               LithoReducer.reduce(lsc, resolveResult, treeId, layoutCache, reductionState)
-          perfEvent?.markerPoint("end_collect_results")
+          perfEvent?.markerPoint("end_reduce")
 
           root?.releaseLayoutPhaseData()