Correctly write Long.toBinaryString as an unsigned value

A previous fix to negative longs incorrectly allowed some positive longs
that would be represented as negative ints to be printed as negative
binary values, instead of as unsigned values. This patch fixes that case
and adds tests to confirm that these edge cases are well represented.
This bug was introduced by 7616ceb.

The binary, hex, and octal tests all fail before this change, the
toString test was just for completeness, but wasn't actually broken.

Fixes #9764

user/super/com/google/gwt/emul/java/lang/Long.java

@@ -237,7 +237,7 @@ private static String toPowerOfTwoUnsignedString(long value, int shift) {
 
     int highBits = LongUtils.getHighBits(value);
     if (highBits == 0) {
-      return Integer.toString((int) value, radix);
+      return Integer.toUnsignedString((int) value, radix);
     }
 
     final int mask = radix - 1;

user/test/com/google/gwt/emultest/java/lang/LongTest.java

@@ -254,6 +254,14 @@ public void testToBinaryString() {
     assertEquals(
         "1111111111111111111111111111111111111111111111111111111111111111",
         Long.toBinaryString(-1));
+
+    // Test int MAX+1 and int -1, as both are positive longs, but negative ints
+    assertEquals(
+        "10000000000000000000000000000000",
+        Long.toBinaryString(((long) Integer.MAX_VALUE) + 1));
+    assertEquals(
+        "11111111111111111111111111111111",
+        Long.toBinaryString(4294967295L));
   }
 
   public void testToHexString() {
@@ -262,6 +270,8 @@ public void testToHexString() {
     assertEquals("1234500000000", Long.toHexString(0x1234500000000L));
     assertEquals("fff1234500000000", Long.toHexString(0xFFF1234500000000L));
     assertEquals("ffffffffffffffff", Long.toHexString(-1));
+    assertEquals("80000000", Long.toHexString(((long) Integer.MAX_VALUE) + 1));
+    assertEquals("ffffffff", Long.toHexString(4294967295L));
   }
 
   public void testToOctalString() {
@@ -270,6 +280,8 @@ public void testToOctalString() {
     assertEquals("1000000000000000000000", Long.toOctalString(Long.MIN_VALUE));
     assertEquals("777777777777777777777", Long.toOctalString(Long.MAX_VALUE));
     assertEquals("1777777777777777777777", Long.toOctalString(-1));
+    assertEquals("20000000000", Long.toOctalString(((long) Integer.MAX_VALUE) + 1));
+    assertEquals("37777777777", Long.toOctalString(4294967295L));
   }
 
   public void testToString() {
@@ -281,6 +293,8 @@ public void testToString() {
     assertEquals("80765", Long.toString(80765L));
     assertEquals("-2147483648", Long.toString((long) Integer.MIN_VALUE));
     assertEquals("2147483647", Long.toString((long) Integer.MAX_VALUE));
+    assertEquals("2147483648", Long.toString(((long) Integer.MAX_VALUE) + 1));
+    assertEquals("4294967295", Long.toString((long) 4294967295L));
     assertEquals("-89000000005", Long.toString(-89000000005L));
     assertEquals("89000000005", Long.toString(89000000005L));
     assertEquals("-9223372036854775808", Long.toString(Long.MIN_VALUE));