compiler: support pragmas on generic functions

[aykevl]

Found this while playing around with some generic code. Luckily the fix is very simple.

[dgryski]

CI failures.

[aykevl]

This is very strange. It looks very much like a race condition of some sort.

EDIT 1:This crashes on macOS, sometimes: go test -short -v -p 1

EDIT 2: well that's great. It definitely looks like a race, but -race doesn't catch it.

[aykevl]

Solid reproducer:

tinygo clean && tinygo build -o test -p 1 ./testdata/generics.go

[aykevl]

Took me a few hours to create a solid reproducer, but here it is: golang/go#59427

[aykevl]

I think I've fixed the issue. Let's see whether the CI passes this time.

[aykevl]

...apparently not. But at least I know how to fix it now.