Fix nvcc dryrun parsing for CUDA 13.3

[mbrobbel]

sccache assumed nvcc-generated cicc and ptxas inputs were always at a fixed offset near the end of the command line. With CUDA 13.3.33, cicc dryrun output can place --simt-only after the input file, which makes the old positional parser treat --simt-only as the input instead of kernel.cpp1.ii.

That can prevent sccache from grouping the cicc and ptxas device compilation steps correctly. Later, fatbinary fails because the expected .cubin files were never produced.

Changes

• Find cicc inputs by .cpp1.ii extension instead of fixed position.
• Find ptxas inputs by .ptx extension instead of fixed position.
• Keep the old positional fallback for unexpected command shapes.
• Add regression coverage for cicc input before --simt-only.
• Add regression coverage for ptxas input detection by .ptx.
• Add nvcc dryrun grouping coverage for CUDA 13.3-style --simt-only.

[sylvestre]

is it reasonable to hardcode .cpp1.ii ?

[mbrobbel]

I think so:

sccache/src/compiler/nvcc.rs

Lines 824 to 827 in 8825b4a

	// If the output file ends with...
	// * .cpp1.ii - cicc/ptxas input
	// * .cpp4.ii - cudafe++ input
	if out_name.ends_with(".cpp1.ii") {

But maybe we should move this into some helpers to make it more obvious?

[sylvestre]

sounds good