Make --input-dir handle gracefully some rare cases

Using `--input-dir path/to/firmware` with a directory containing:

  path/to/firmware/firmware.ino.bin
  path/to/firmware/some_other_firmware_name.ino.bin

should not fail but select `firmware.ino.bin` for upload because the
containing folder has the same name.

See arduino#765 (comment)

commands/upload/upload.go

@@ -438,6 +438,15 @@ func detectSketchNameFromBuildPath(buildPath *paths.Path) (string, error) {
 		return "", err
 	}
 
+	if absBuildPath, err := buildPath.Abs(); err == nil {
+		candidateName := absBuildPath.Base() + ".ino"
+		f := files.Clone()
+		f.FilterPrefix(candidateName + ".")
+		if f.Len() > 0 {
+			return candidateName, nil
+		}
+	}
+
 	candidateName := ""
 	var candidateFile *paths.Path
 	for _, file := range files {

commands/upload/upload_test.go

@@ -97,6 +97,11 @@ func TestDetermineBuildPathAndSketchName(t *testing.T) {
 		{"", "testdata/build_path_2", blonk, fqbn, "testdata/build_path_2", "Blink.ino"},
 		// 15: error: used both importPath and importFile
 		{"testdata/build_path_2/Blink.ino.hex", "testdata/build_path_2", blonk, fqbn, "<nil>", ""},
+
+		// 16: importPath containing multiple firmwares, but one has the same name as the containing folder
+		{"", "testdata/firmware", nil, fqbn, "testdata/firmware", "firmware.ino"},
+		// 17: importFile among multiple firmwares
+		{"testdata/firmware/another_firmware.ino.bin", "", nil, fqbn, "testdata/firmware", "another_firmware.ino"},
 	}
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("SubTest%02d", i), func(t *testing.T) {