We still set a lot of macros depending on specific gcc versions. All
these old versions are unsupported by now anyways, so we can also just
define these macros as 1.
If this CL sticks for a while, we can start actually cleaning up all
code relying on these macros, as most of them should be 1 now on all
platforms.

R=ulan@chromium.org

Bug: v8:9810
Change-Id: I2f9c55170091f8c263deeddfb7ff89e5b2a0bb12
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1862564Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64413}