Use one declaration per statement

The old style of merging all of a function's variable declarations into
a single statement made some sense back in the days of var, but there's
no reason to keep doing it now that we use const and let.

spec/core/asymmetric_equality/ArrayWithExactContentsSpec.js

@@ -32,9 +32,9 @@ describe('ArrayWithExactContents', function() {
   });
 
   it('jasmineToStrings itself', function() {
-    const sample = [],
-      matcher = new privateUnderTest.ArrayWithExactContents(sample),
-      pp = jasmine.createSpy('pp').and.returnValue('sample');
+    const sample = [];
+    const matcher = new privateUnderTest.ArrayWithExactContents(sample);
+    const pp = jasmine.createSpy('pp').and.returnValue('sample');
 
     expect(matcher.jasmineToString(pp)).toEqual(
       '<jasmine.arrayWithExactContents(sample)>'