Merge pull request #10569 from ethereum/byteArrayStorageStorage

Fix copying byte arrays from storage to storage.

test/libsolidity/semanticTests/array/copying/bytes_storage_to_storage.sol

@@ -0,0 +1,26 @@
+contract c {
+    bytes a;
+    bytes b;
+    function f(uint len) public returns (bytes memory) {
+        bytes memory x = new bytes(len);
+        for (uint i = 0; i < len; i++)
+            x[i] = byte(uint8(i));
+        a = x;
+        for (uint i = 0; i < len; i++)
+            assert(a[i] == x[i]);
+        b = a;
+        for (uint i = 0; i < len; i++)
+            assert(b[i] == x[i]);
+        return b;
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f(uint256): 0 -> 0x20, 0x00
+// f(uint256): 31 -> 0x20, 0x1f, 0x0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e00
+// f(uint256): 32 -> 0x20, 0x20, 1780731860627700044960722568376592200742329637303199754547598369979440671
+// f(uint256): 33 -> 0x20, 33, 1780731860627700044960722568376592200742329637303199754547598369979440671, 0x2000000000000000000000000000000000000000000000000000000000000000
+// f(uint256): 63 -> 0x20, 0x3f, 1780731860627700044960722568376592200742329637303199754547598369979440671, 14532552714582660066924456880521368950258152170031413196862950297402215316992
+// f(uint256): 12 -> 0x20, 0x0c, 0x0102030405060708090a0b0000000000000000000000000000000000000000
+// f(uint256): 129 -> 0x20, 0x81, 1780731860627700044960722568376592200742329637303199754547598369979440671, 0x202122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f, 29063324697304692433803953038474361308315562010425523193971352996434451193439, 0x606162636465666768696a6b6c6d6e6f707172737475767778797a7b7c7d7e7f, -57896044618658097711785492504343953926634992332820282019728792003956564819968