sl/cont_shape: improve dupe detection in ImpliedShapeDetector
sl/symtrace: track entailment with EntailmentNode
sl/symtrace: highlight "default" edges by blue color
sl/symstate: preserve entailment trace nodes
sl/symstate: add compile-time opt SE_FORBID_HEAP_REPLACE
sl/fixed_point: deal better with entailment trace nodes
sl/sym{heap,trace}: hide recoverable crashes in production