Add Memory utility library (#5189)

Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>
Co-authored-by: Arr00 <13561405+arr00@users.noreply.github.com>

test/utils/Memory.t.sol

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.20;
+
+import {Test} from "forge-std/Test.sol";
+import {Memory} from "@openzeppelin/contracts/utils/Memory.sol";
+
+contract MemoryTest is Test {
+    using Memory for *;
+
+    // - first 0x80 bytes are reserved (scratch + FMP + zero)
+    uint256 constant START_PTR = 0x80;
+    // - moving the free memory pointer to far causes OOG errors
+    uint256 constant END_PTR = type(uint24).max;
+
+    function testGetsetFreeMemoryPointer(uint256 seed) public pure {
+        bytes32 ptr = bytes32(bound(seed, START_PTR, END_PTR));
+        ptr.asPointer().setFreeMemoryPointer();
+        assertEq(Memory.getFreeMemoryPointer().asBytes32(), ptr);
+    }
+}