Don't run the system linker unncessarily.
Don't run the system linker unncessarily.

This wastes time when evaluating expressions in GHCi. We also
disable object unloading when using the dynamic linker, too.

Fixes #7382. Fixes #7326.

Signed-off-by: Austin Seipp <48c905ac3851f382b914247d97dd93273d5ff555@pobox.com>

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