Fix OVERWRITING_CLOSURE story for shrunk arrays

Commits:

• rts: Fix nomenclature in OVERWRITING_CLOSURE macros

The additional commentary introduced by commit 8916e64e ("Implement shrinkSmallMutableArray# and resizeSmallMutableArray#.") unfortunately got this wrong. We set 'prim' to true in overwritingClosureOfs because we don't want to call LDV_recordDead().

The reason is because of this "inherently used" distinction made in the LDV profiler so I rename the variable to be more appropriate.

• Remove call to LDV_RECORD_CREATE for array resizing

(See updated note in diff)

• rts: Assert LDV_recordDead is not called for inherently used closures

The comments make it clear LDV_recordDead should not be called for inhererently used closures, so add an assertion to codify this fact.

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