add more alignment behavior test coverage

test/behavior/align_stage1.zig

@@ -223,3 +223,18 @@ test "align(N) on functions" {
 fn overaligned_fn() align(0x1000) i32 {
     return 42;
 }
+
+test "page aligned array on stack" {
+    // Large alignment value to make it hard to accidentally pass.
+    var array align(0x1000) = [_]u8{ 1, 2, 3, 4, 5, 6, 7, 8 };
+    var number1: u8 align(16) = 42;
+    var number2: u8 align(16) = 43;
+
+    try expect(@ptrToInt(&array[0]) & 0xFFF == 0);
+    try expect(array[3] == 4);
+
+    try expect(@truncate(u4, @ptrToInt(&number1)) == 0);
+    try expect(@truncate(u4, @ptrToInt(&number2)) == 0);
+    try expect(number1 == 42);
+    try expect(number2 == 43);
+}