HLSL: Initializing constant through global function causes invalid recursion error

Compiling the following valid hlsl code as a compute shader:
```hlsl
struct TestConstants {
float a;
};
static TestConstants DefaultConstants() {
TestConstants constants;
constants.a = 1.0f;
return constants;
}
static const TestConstants constants = DefaultConstants();
void main() { }
```

Incorrectly generates the link error:
```
ERROR: Linking compute stage: Recursion detected:
DefaultConstants( calling DefaultConstants(
```

Use the supplied HLSL compute-shader reproducer as the first test and inspect how the compiler and linker handle the global function used to initialize the constant. Done means this valid shader compiles without the false recursive-call linking error.

Written by the indexing model from the issue text.