const runtime.scavChunkFlagsMask

2 uses

	runtime (current package)
		mgcscavenge.go#L1270: 		scavChunkFlags: scavChunkFlags(uint8(sc>>(16+logScavChunkInUseMax)) & scavChunkFlagsMask),
		mgcscavenge.go#L1299: 	scavChunkFlagsMask = (1 << scavChunkMaxFlags) - 1