Auto merge of #110784 - cuviper:build-gcc-https, r=jyn514

Revert "Download the GCC sources insecurely"

This reverts commit 3da037f.

This workaround was added after TLS problems with Debian 6 were noted in <rust-lang/rust#86586 (comment)>, but we should be well past that since #95026, where our oldest images are now based on CentOS 7.

Author: bors