runtime: regression segfault on linux 3.4 on mipsle [1.26 backport]

[gopherbot]

@Jorropo requested issue #77730 to be considered for backport to the next 1.26 minor release.

@gopherbot please open a backport issue for 1.26

It makes 1.26 compiled go programs (incl the toolchain) completely unusable on 32 bits mips machines running linux <5.0 (or <5.1) which include many versions of linux above our minimum supported kernel version.
The program will always crash in the runtime when trying to do some futex operations.

[gopherbot]

Change https://go.dev/cl/747663 mentions this issue: runtime: fix value of ENOSYS on mips from 38 to 89

[wwqgtxx]

I'd like to inquire about the progress. I see that version 1.26.1 is scheduled for release on Thursday, March 5th. Could you please merge the CL before the release? Otherwise, we'll have to wait another month to update the MIPSLE platform to the 1.26 toolchain.

[Jorropo]

@wwqgtxx the backport cannot be merged since the fix isn't in master yet;

The fix isn't in master yet because no one (else but me*) with +2 review & merge capabilities sent +2 review.
Then we need to get +1 but theses are really fast and easy to get.
Then I can merge.

Then someone might take a look at the backport.

FWIW I guess this might make it in 1.26.2.

*I can't review my own CLs for obvious reasons.