Clip OOB values in call data load and copy (#448)

The OOB logic is implemented in the runtime but truncation circumvented
it.

Closes #263

---------

Signed-off-by: xermicus <cyrill@parity.io>
Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>

crates/integration/codesize.json

@@ -1,10 +1,10 @@
 {
-  "Baseline": 911,
-  "Computation": 2337,
-  "DivisionArithmetics": 14488,
-  "ERC20": 17189,
-  "Events": 1672,
-  "FibonacciIterative": 1454,
-  "Flipper": 2106,
-  "SHA1": 7814
+  "Baseline": 864,
+  "Computation": 2323,
+  "DivisionArithmetics": 14475,
+  "ERC20": 17229,
+  "Events": 1663,
+  "FibonacciIterative": 1421,
+  "Flipper": 2154,
+  "SHA1": 7751
 }