[TIMOB-26945] iOS: Investigate slow boot time

There recently have been great improvements on the build time thanks to [~cwilliams] and [~jvennemann]! The next thing to fine-tune Titanium would be to identify the quite slow boot time compared to native apps. For us, the boot process usually takes 2-5 seconds depending on the device. We do some require() stuff in the Alloy.js, so that could maybe optimized out to a later point, but I'd be curious if there are some locks (especially mutex locks) left overs from the bad old kroll-thread times that delayed the boot on purpose.