A workaround was found thanks to "lembacon" on the Apple Developer Forums.
In Terminal:
cd /Applications/Xcode-beta.app (or wherever your Xcode 7 beta 4 is located)
cd Contents/Developer/Platforms/iPhoneSimulator.platform
cd Developer/SDKs/iPhoneSimulator.sdk/usr/lib
sudo mv dyld_sim dyld_sim.orig
Seems to work for iOS projects but watchOS is iffy.
EDIT: watchOS solution:
cd /Applications/Xcode-beta.app (or wherever your Xcode 7 beta 4 is located)
cd Contents/Developer/Platforms/WatchSimulator.platform
cd Developer/SDKs/WatchSimulator.sdk/usr/lib
sudo mv dyld_sim dyld_sim.orig
Another Edit: As mentioned by sciasxp, this also works for 6.4. Hopefully we‘ll get new iOS and Xcode betas soon that permanently fix this.
Another Another Edit: A new iOS beta is out today, as well as a new Xcode beta. This issue should be resolved.
