Fix JankTracker multimap lookups.

Fixes the layer-to-listeners multimap lookups in the jank tracker to
ensure it gets the right listeners by using the equal_range lookup.

Bug: b/392849939
Test: manual, libsurfaceflinger_unittest, SysUI perf tests
Flag: EXEMPT bugfix
Change-Id: Iff96da68d278e6c0ac8be86a4410a8dcd0abdad0