Fix NPE from unintialized logger in GenotypingEngine (#8159)

* Fixes ##8158

src/main/java/org/broadinstitute/hellbender/tools/walkers/genotyper/GenotypingEngine.java

@@ -70,6 +70,7 @@ protected GenotypingEngine(final Config configuration,
         this.samples = samples;
         this.doAlleleSpecificCalcs = doAlleleSpecificCalcs;
         logger = LogManager.getLogger(getClass());
+        oneShotLogger = new OneShotLogger(logger);
         numberOfGenomes = this.samples.numberOfSamples() * configuration.genotypeArgs.samplePloidy;
         alleleFrequencyCalculator = AlleleFrequencyCalculator.makeCalculator(configuration.genotypeArgs);
     }