fix handling of 64-bit arguments to Method.invoke on 32-bit architectures

The previous code failed to account for alignment padding in the
Double and Long classes.

src/compile.cpp

@@ -8033,8 +8033,7 @@ class ArgumentList {
       
       case 'J':
       case 'D':
-        addLong(cast<int64_t>(objectArrayBody(t, arguments, index++),
-                              BytesPerWord));
+        addLong(cast<int64_t>(objectArrayBody(t, arguments, index++), 8));
         break;
 
       default:

src/interpret.cpp

@@ -2772,8 +2772,7 @@ pushArguments(Thread* t, object this_, const char* spec, object a)
       
     case 'J':
     case 'D':
-      pushLong(t, cast<int64_t>(objectArrayBody(t, a, index++),
-                                BytesPerWord));
+      pushLong(t, cast<int64_t>(objectArrayBody(t, a, index++), 8));
       break;
 
     default:

test/Floats.java

@@ -83,7 +83,25 @@ public class Floats {
     }
   }
 
-  public static void main(String[] args) {
+  public static class Rectangle {
+    public double x;
+    public double y;
+    public double width;
+    public double height;
+
+    public void setX(double x) {
+      this.x = x;
+    }
+  }
+
+  public static void main(String[] args) throws Exception {
+    expect(new Double(42.0) == 42.0);
+
+    { Rectangle r = new Rectangle();
+      Rectangle.class.getMethod("setX", double.class).invoke(r, 42.0);
+      expect(r.x == 42.0);
+    }
+
     { double input[] = new double[8];
       double left[] = new double[8];
       double right[] = new double[8];

test/Longs.java

@@ -65,9 +65,25 @@ public class Longs {
     return x >>> 32;
   }
 
+  public static class Rectangle {
+    public long x;
+    public long y;
+    public long width;
+    public long height;
+
+    public void setX(long x) {
+      this.x = x;
+    }
+  }
+
   public static void main(String[] args) throws Exception {
     expect(volatileLong == getConstant());
 
+    { Rectangle r = new Rectangle();
+      Rectangle.class.getMethod("setX", long.class).invoke(r, 42L);
+      expect(r.x == 42L);
+    }
+
     { long a = 0x1FFFFFFFFL;
       long b = -1;
       expect(a != b);