test: crypto-hash-stream-pipe use strict equal

Replaces the use of assert.equal() with assert.strictEqual in test
code.

PR-URL: #9935
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

test/parallel/test-crypto-hash-stream-pipe.js

@@ -14,7 +14,7 @@ var h = crypto.createHash('sha1');
 var expect = '15987e60950cf22655b9323bc1e281f9c4aff47e';
 
 s.pipe(h).on('data', common.mustCall(function(c) {
-  assert.equal(c, expect);
+  assert.strictEqual(c, expect);
 })).setEncoding('hex');
 
 s.end('aoeu');