Use JUnit 5 convention for class visibility

Fix Checkstyle issues

Author: garydgregory

src/test/java/org/apache/commons/imaging/formats/ico/IcoRoundtripTest.java

@@ -261,7 +261,7 @@ public byte[] generateBitmap(final int foreground, final int background, final i
 
     private final Map<Integer, BitmapGenerator> generatorMap = new HashMap<>();
 
-    public IcoRoundtripTest() {
+    IcoRoundtripTest() {
         generatorMap.put(1, new GeneratorFor1BitBitmaps());
         generatorMap.put(4, new GeneratorFor4BitBitmaps());
         generatorMap.put(8, new GeneratorFor8BitBitmaps());

src/test/java/org/apache/commons/imaging/formats/png/PngWritePredictorTest.java

@@ -39,7 +39,7 @@ class PngWritePredictorTest {
     public static void setUpClass() {
     }
 
-    public PngWritePredictorTest() {
+    PngWritePredictorTest() {
     }
 
     /**

src/test/java/org/apache/commons/imaging/formats/tiff/TiffFloatingPointMultivariableTest.java

@@ -58,7 +58,7 @@ class TiffFloatingPointMultivariableTest extends AbstractTiffTest {
     float f1 = 1.0F;
     float[] fSample = new float[width * height * samplesPerPixel];
 
-    public TiffFloatingPointMultivariableTest() {
+    TiffFloatingPointMultivariableTest() {
         for (int iPlane = 0; iPlane < 2; iPlane++) {
             final int pOffset = iPlane * width * height;
             for (int iRow = 0; iRow < height; iRow++) {

src/test/java/org/apache/commons/imaging/formats/tiff/TiffFloatingPointRoundTripTest.java

@@ -58,7 +58,7 @@ class TiffFloatingPointRoundTripTest extends AbstractTiffTest {
     float[] f = new float[width * height];
     int[] argb = new int[width * height];
 
-    public TiffFloatingPointRoundTripTest() throws ImagingException, IOException {
+    TiffFloatingPointRoundTripTest() throws ImagingException, IOException {
         // populate the image data
         for (int iCol = 0; iCol < width; iCol++) {
             final float s = iCol / (float) (width - 1);

src/test/java/org/apache/commons/imaging/formats/tiff/TiffRasterDataIntTest.java

@@ -34,7 +34,7 @@ class TiffRasterDataIntTest {
     AbstractTiffRasterData raster;
     float meanValue;
 
-    public TiffRasterDataIntTest() {
+    TiffRasterDataIntTest() {
         double sum = 0;
         data = new int[width * height];
         int k = 0;

src/test/java/org/apache/commons/imaging/formats/tiff/TiffRasterDataTest.java

@@ -34,7 +34,7 @@ class TiffRasterDataTest {
     AbstractTiffRasterData raster;
     float meanValue;
 
-    public TiffRasterDataTest() {
+    TiffRasterDataTest() {
         double sum = 0;
         data = new float[width * height];
         int k = 0;

src/test/java/org/apache/commons/imaging/formats/tiff/TiffRasterStatisticsTest.java

@@ -38,7 +38,7 @@ class TiffRasterStatisticsTest {
     TiffRasterStatistics stat0;
     TiffRasterStatistics stat1;
 
-    public TiffRasterStatisticsTest() {
+    TiffRasterStatisticsTest() {
         double sum = 0;
         data = new float[width * height];
         int k = 0;

src/test/java/org/apache/commons/imaging/formats/tiff/TiffRoundTripInt32Test.java

@@ -51,7 +51,7 @@ class TiffRoundTripInt32Test extends AbstractTiffTest {
 
     int[] sample = new int[width * height];
 
-    public TiffRoundTripInt32Test() {
+    TiffRoundTripInt32Test() {
         // populate the image data
         for (int iCol = 0; iCol < width; iCol++) {
             for (int iRow = 0; iRow < height; iRow++) {

src/test/java/org/apache/commons/imaging/formats/tiff/TiffShortIntRoundTripTest.java

@@ -51,7 +51,7 @@ class TiffShortIntRoundTripTest extends AbstractTiffTest {
 
     short[] sample = new short[width * height];
 
-    public TiffShortIntRoundTripTest() {
+    TiffShortIntRoundTripTest() {
         // populate the image data
         for (int iCol = 0; iCol < width; iCol++) {
             for (int iRow = 0; iRow < height; iRow++) {

src/test/java/org/apache/commons/imaging/formats/tiff/photometricinterpreters/floatingpoint/PaletteEntryForRangeTest.java

@@ -30,7 +30,7 @@
  */
 class PaletteEntryForRangeTest {
 
-    public PaletteEntryForRangeTest() {
+    PaletteEntryForRangeTest() {
     }
 
     /**