This PR modifies the FactManager methods IdIsIrrelevant and GetIrrelevantIds so
that an id is always considered irrelevant if it comes from a dead block.
Fixes#3733.
For FuzzerPassAddParameters, adds pointer types (that have the storage
class Function or Private) to the pool of available types for new
parameters. If there are no variables of the chosen pointer type, it
invokes TransformationAddLocalVariable / TransformationAddGlobalVariable
to add one.
Part of #3403
