test: ignore environment-dependent multiqc_plots in default test snapshot

MultiQC renders multiqc_plots/ (pdf/png/svg) on linux/amd64 (CI) but not on
all local archs, so the file-list (stable_name) snapshot of the default test
was env-dependent and failed on CI. Exclude multiqc_plots/ from stable_name
(stable_path already ignores the plot files via .nftignore).

Author: znorgaard

tests/default.nf.test

@@ -14,7 +14,9 @@ nextflow_pipeline {
 
         then {
             // stable_name: All files + folders in ${params.outdir}/ with a stable name
-            def stable_name = getAllFilesFromDir(params.outdir, relative: true, includeDir: true, ignore: ['pipeline_info/*.{html,json,txt}'])
+            // multiqc_plots/ exports are environment-dependent (rendered on linux/amd64 CI but not on
+            // some local arch), so exclude them from the file-list snapshot for stability.
+            def stable_name = getAllFilesFromDir(params.outdir, relative: true, includeDir: true, ignore: ['pipeline_info/*.{html,json,txt}', 'multiqc/multiqc_plots', 'multiqc/multiqc_plots/**'])
             // stable_path: All files in ${params.outdir}/ with stable content
             def stable_path = getAllFilesFromDir(params.outdir, ignoreFile: 'tests/.nftignore')
             // bam_files: All bam files