Implemented CPU plugin just-in-time emitter for SoftPlus operation.

[geeky33]

Details:

Add ARM64 JIT emitter implementation for SoftPlus operation (ln(1 + exp(x))) with fp32 support.

• Changes include:
• Implement SoftPlus JIT emitter using ARM NEON instructions
• Add kernel support in ARM64 executor
• Add test coverage for JIT SoftPlus operation
• Included comprehensive unit tests and performance benchmarks. Verified against reference CPU implementation with proper handling of edge cases (NaN, infinity, denormals).

No breaking changes. Requires ARM64 platform with NEON SIMD support.

@eshoguli
@dmitry-gorokhov
@a-sidorova
@p-wysocki

Tickets:

• [Good First Issue] [ARM]: Implement CPU plugin just-in-time emitter for SoftPlus operation #24109