fix(REVERT): remove zone internal stack frames in error.stack (angula…

…r#632)

This feature was reverted because it was causing a performance regression. 
The setup of all of the stack traces added about 20-25ms to the total 
time of the Zone initialization. This was a bit more than 50% of overall
time zone needed to initialize. While this is a useful feature, the 
performance cost does not justify its cost.