Performance: optimize ArrayHitCounter increment method (benchmarks improved by up to 10%)

[alexklibisz]

Related Issue

#611

Changes

Making two slight optimizations within ArrayHitCounter:

1. Get rid of an overloaded method call
2. Doing the check-and-increment in a single operation rather than two separate operations

This improves the Fashion Mnist benchmarks by up to 10%:

Testing and Validation

Standard CI and benchmarks