buffer: coerce offset using Math.trunc()

lib/buffer.js

@@ -807,8 +807,10 @@ Buffer.prototype.toJSON = function() {
 
 
 function adjustOffset(offset, length) {
-  offset |= 0;
-  if (offset === 0) {
+  // Use Math.trunc() to convert offset to an integer value that can be larger
+  // than an Int32. Hence, don't use offset | 0 or similar techniques.
+  offset = Math.trunc(offset);
+  if (offset === 0 || Number.isNaN(offset)) {
     return 0;
   } else if (offset < 0) {
     offset += length;

test/parallel/test-buffer-slice.js

@@ -72,3 +72,30 @@ assert.strictEqual(0, Buffer.from('hello').slice(0, 0).length);
     'bcd'
   );
 }
+
+{
+  const buf = Buffer.from('abcdefg');
+  assert.strictEqual(buf.slice(-(-1 >>> 0) - 1).toString(), buf.toString());
+}
+
+{
+  const buf = Buffer.from('abc');
+  assert.strictEqual(buf.slice(-0.5).toString(), buf.toString());
+}
+
+{
+  const buf = Buffer.from([
+    1, 29, 0, 0, 1, 143, 216, 162, 92, 254, 248, 63, 0,
+    0, 0, 18, 184, 6, 0, 175, 29, 0, 8, 11, 1, 0, 0
+  ]);
+  const chunk1 = Buffer.from([
+    1, 29, 0, 0, 1, 143, 216, 162, 92, 254, 248, 63, 0
+  ]);
+  const chunk2 = Buffer.from([
+    0, 0, 18, 184, 6, 0, 175, 29, 0, 8, 11, 1, 0, 0
+  ]);
+  const middle = buf.length / 2;
+
+  assert.deepStrictEqual(buf.slice(0, middle), chunk1);
+  assert.deepStrictEqual(buf.slice(middle), chunk2);
+}