Capture PDBs in --make-repro-path (#121163)

Repro for dotnet/roslyn#80952 was somewhat harder to obtain because we
don't pack PDBs into the repro package (they are not command line
arguments and the compiler looks for them next to the assembly).

This is a simple change to just look for .pdb files next to the files
we're packing.

Cc @dotnet/ilc-contrib

Author: MichalStrehovsky

src/coreclr/tools/Common/CommandLineHelpers.cs

@@ -311,9 +311,22 @@ string ConvertFromOriginalPathToReproPackagePath(bool input, string originalPath
                         string reproFileDir = prefix + originalToReproPackageFileName.Count.ToString() + Path.DirectorySeparatorChar;
                         reproPackagePath = Path.Combine(reproFileDir, Path.GetFileName(originalPath));
                         if (!input)
+                        {
                             archive.CreateEntry(reproFileDir); // for outputs just create output directory
+                        }
                         else
+                        {
                             archive.CreateEntryFromFile(originalPath, reproPackagePath);
+
+                            // The compiler probes for .pdb files next to input assemblies. For simplicity, just try to look
+                            // for PDB next to any file we package.
+                            string originalPdbPath = Path.ChangeExtension(originalPath, "pdb");
+                            if (!string.Equals(originalPath, originalPdbPath, StringComparison.InvariantCultureIgnoreCase)
+                                && File.Exists(originalPdbPath))
+                            {
+                                archive.CreateEntryFromFile(originalPdbPath, Path.ChangeExtension(reproPackagePath, "pdb"));
+                            }
+                        }
                         originalToReproPackageFileName.Add(originalPath, reproPackagePath);
 
                         return reproPackagePath;