Has anyone experienced a performance drop in Google Chrome, version 37 and above, when adding a new property to an object?

Question

Google Chrome

I'm running a browser performance test at jsperf.com/add-to-object
The test initializes quickly and passes quickly on FF, IE, Chromium 40.0.2211.0 browsers, but on Google Chrome versions 37, 38, 39(beta), 40( dev), initialization takes a very long time and you can wait 5-10 minutes until the test itself starts, while a window may appear several times asking you to stop working or wait. The problem appeared directly with the 37.0.2062.94 version of Chrom. There is a suspicion that the algorithm for adding new elements containing non-numeric characters as identifiers has broken. When using a number as an identifier, everything works quickly.
Has anyone encountered a similar problem? Did you get around it somehow?