test: add block scoping to test-assert-deep

Add block scoping to test-assert-deep.js to reduce likelihood of one
test case having side effects that affect another test case.

PR-URL: https://github.com/nodejs/node/pull/16532
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Minwoo Jung <minwoo@nodesource.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>

test/parallel/test-assert-deep.js

@@ -34,18 +34,22 @@ assert.throws(() => assert.deepStrictEqual(arr, buf),
               re`${arr} deepStrictEqual ${buf}`);
 assert.doesNotThrow(() => assert.deepEqual(arr, buf));
 
+{
   const buf2 = Buffer.from(arr);
   buf2.prop = 1;
 
   assert.throws(() => assert.deepStrictEqual(buf2, buf),
                 re`${buf2} deepStrictEqual ${buf}`);
   assert.doesNotThrow(() => assert.deepEqual(buf2, buf));
+}
 
+{
   const arr2 = new Uint8Array([120, 121, 122, 10]);
   arr2.prop = 5;
   assert.throws(() => assert.deepStrictEqual(arr, arr2),
                 re`${arr} deepStrictEqual ${arr2}`);
   assert.doesNotThrow(() => assert.deepEqual(arr, arr2));
+}
 
 const date = new Date('2016');
 
@@ -85,6 +89,7 @@ assert.throws(() => assert.deepStrictEqual(re1, re2),
 
 // For these weird cases, deepEqual should pass (at least for now),
 // but deepStrictEqual should throw.
+{
   const similar = new Set([
     { 0: '1' },  // Object
     { 0: 1 },  // Object
@@ -113,6 +118,7 @@ for (const a of similar) {
       }
     }
   }
+}
 
 common.expectsError(() => {
   assert.deepEqual(new Set([{ a: 0 }]), new Set([{ a: 1 }]));