leon: Add another Spacebel test, 1651, to test large range of small int.

leon-tests/spacebel_tickets/SPB_1651.exp

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+MemoryError

leon-tests/spacebel_tickets/SPB_1651.py

+# test that small int range is 2**46-1
+
+import micropython
+
+def check(n):
+    micropython.heap_lock()
+    x = -(2**(n - 1)) * 2
+    y = -(x + 1)
+    print(x)
+    print(y)
+    micropython.heap_unlock()
+
+check(43)
+check(44)
+check(45)
+check(46)
+
+try:
+    check(47)
+except MemoryError:
+    print('MemoryError')