Try to fix the GNU make CI workflow.

For AppleClang, drop C++11 and C++14 from the build matrix: Abseil
doesn't support C++11 anymore; and Abseil as installed by Homebrew
is currently built for C++17.

For GCC, omit `sudo` due to "sudo: command not found" errors. Note
that the GCC jobs run under Docker, so...

Change-Id: Id6cf1de1cf6b8ec81411b46f236adccbce86b2f9
Reviewed-on: https://code-review.googlesource.com/c/re2/+/61271
Reviewed-by: Alex Chernyakhovsky <achernya@google.com>
Reviewed-by: Paul Wankadia <junyer@google.com>