slang-test/WGPU: IR opcode during code emit

[aleino-nv]

This output is generated by
slang-test -bindir %BINDIR% -category full -api wgpu tests/autodiff/custom-intrinsic.slang

...
error: ERROR:
EXPECTED{{{
result code = 0
standard error = {
}
standard output = {
}
}}}
ACTUAL{{{
result code = 1
standard error = {
}
standard output = {
abort compilation: tests/autodiff/custom-intrinsic.slang(21): internal error 99999: unimplemented feature in Slang compiler: unexpected IR opcode during code emit
    T myexp(T x);
      ^~~~~
}
}}}

error: ERROR:
EXPECTED{{{
type: float
7.389056
7.389056
0.0
0.0
0.0}}}
ACTUAL{{{
}}}

...

Tests:

• tests/autodiff/custom-intrinsic.slang

[bmillsNV]

Test needs to be disabled.

[aleino-nv]

Fixing might be easy.