Skip denormal disabler on MOD Audio builds

[falkTX]

For MOD Audio units the host disables denormals on all audio threads. Thus this part of the code can be disabled as it is both useless and unwanted.

Alternatively make this a generic compile-time option? So others can disable that part of the code too. Up to you

[mikeoliphant]

Resolved via https://github.com/mikeoliphant/neural-amp-modeler-lv2/commit/0aad7c32b6806c826848b21bb1d2699eb79de29b