RPC: small optimizations (#2564)

cmd/rpcdaemon/commands/call_traces_test.go

cmd/rpcdaemon/commands/trace_filtering.go

common/hexutil/json.go

core/state/history.go

core/state/history_test.go

core/state/plain_readonly.go

core/vm/instructions.go

core/vm/interpreter.go

ethdb/bitmapdb/dbutils.go

rpc/handler.go

turbo/adapter/reader.go