DXILCounters.cpp isn't copied when HLSL_COPY_GENERATED_SOURCES is set

[damyanp]

What it looks like happened:

• DXILCounters.cpp gets regenerated by codegen, but isn't copied when HLSL_COPY_GENERATED_SOURCES is set
• While working on this, copilot was manually updating the generated files from tmp, rather than relying on HLSL_COPY_GENERATED_SOURCES to do it.
• This resulted in DXILCounters.cpp getting updated for the first time in quite a while, hence lots of seemingly unrelated changes.

Is DxilCounters.cpp meant to be getting updated regularly?

Originally posted by @damyanp in #8291 (comment)