test: lib: flat_mutation_reader_assertion: Add trace-level logging of read fragments
test: lib: flat_mutation_reader_assertion: Add trace-level logging of read fragments

Message-Id: <af70a2d97caf01d1ccefed47783b4e18625ab8be@scylladb.com>

scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla