Added prerequisites on AddBuildBoardProperty* test

Signed-off-by: Cristian Maglie <c.maglie@arduino.cc>

Author: cmaglie

src/arduino.cc/builder/test/add_build_board_property_if_missing_test.go

@@ -39,6 +39,8 @@ import (
 )
 
 func TestAddBuildBoardPropertyIfMissing(t *testing.T) {
+	DownloadCoresAndToolsAndLibraries(t)
+
 	ctx := &types.Context{
 		HardwareFolders: []string{filepath.Join("..", "hardware"), "hardware", "downloaded_hardware", "user_hardware"},
 		FQBN:            "my_avr_platform:avr:mymega",
@@ -66,6 +68,8 @@ func TestAddBuildBoardPropertyIfMissing(t *testing.T) {
 }
 
 func TestAddBuildBoardPropertyIfMissingNotMissing(t *testing.T) {
+	DownloadCoresAndToolsAndLibraries(t)
+
 	ctx := &types.Context{
 		HardwareFolders: []string{filepath.Join("..", "hardware"), "hardware", "downloaded_hardware", "user_hardware"},
 		FQBN:            "my_avr_platform:avr:mymega:cpu=atmega2560",