Allocate spscQueue for metrics on demand

Since IPCThreadState is created for most threads,
it is more efficient to create the queue on demand.

Bug: 429099044
Bug: 407694522
Test: atest binderUnitTest
Flag: build.RELEASE_LIBBINDER_BINDER_OBSERVER
Change-Id: I741e6dc0fb45e31316ef2787849810939039c323