Update test expectation for "100 GET requests 50k"

Locally Node v7 and v8 also have higher memory expectations,
so just use the same maximum memory value for v0.x and non-v0.x.

Author: Rob--W

test/test-memory.js

@@ -93,10 +93,7 @@ describe('memory usage', function() {
 
   it('100 GET requests 50k', function(done) {
     // This test is just for comparison with the following tests.
-    // On Node 0.10.x, the initial memory usage seems higher on Travis, so use
-    // a higher maximum value to avoid flaky tests.
-    var memMax = /^v0\./.test(process.version) ? 1200 : 550;
-    performNRequests(100, 50, memMax, done);
+    performNRequests(100, 50, 1200, done);
   });
 
   // 100x 1k and 100x 50k for comparison.