[java/cs] Add some parseInt tests from #4132 and fix them on java/cs

Related to #4051

std/cs/_std/Std.hx

@@ -81,7 +81,7 @@ import cs.internal.Exceptions;
 			}
 		}
 
-		var foundAny = false;
+		var foundAny = i != -1;
 		var isNeg = false;
 		while (++i < len)
 		{

std/java/_std/Std.hx

@@ -79,7 +79,7 @@ import java.internal.Exceptions;
 			}
 		}
 
-		boolean foundAny = false;
+		boolean foundAny = i != 0;
 		boolean isNeg = false;
 		for (; i < len; i++)
 		{

tests/unit/src/unitstd/Std.unit.hx

@@ -88,6 +88,8 @@ Std.parseFloat("2.426670815e+12") == 2.426670815e+12;
 Std.parseFloat("2.426670815E+12") == 2.426670815e+12;
 Std.parseFloat("2.426670815e-12") == 2.426670815e-12;
 Std.parseFloat("2.426670815E-12") == 2.426670815e-12;
+Std.parseInt("0x C") == 0;
+Std.parseInt("0x+A") == 0;
 
 // random
 var x = Std.random(2);