Turn some alloca_no_lifetime() calls into plain alloca() calls
Turn some alloca_no_lifetime() calls into plain alloca() calls

The issues that the comments referred to were fixed before the PR even
landed but we never got around to remove the hack of skipping the
lifetime start.

GBGamer/rust,graydon/rust,GBGamer/rust,graydon/rust,aidancully/rust,aidancully/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,graydon/rust,GBGamer/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,GBGamer/rust