LayerTraceGenerator: Fix duplicate layer ids

Layers can be created from API calls on the binder thread or
by surfaceflinger on the main thread for mirroring and
BSL background layers. Transaction traces keep track of
layer creation API calls to recreate layers when generating
the layer trace.

However, there was a possibility that new layers would be
recorded with a set of transactions that were applied with
an earlier vsync. This is harmless except we could end up
creating layers with duplicate layer ids since layers created
via binder would get an injected sequence id while main
thread created layers would use the global counter.

Test: atest transactiontrace_testsuite
Bug: 235376060
Change-Id: Ia11839d1880bc131ab5314779281c93393d6742f