testsuite: go: Require split-stack support for go.test/test/index0.go [PR87589]

testsuite: go: Require split-stack support for go.test/test/index0.go [PR87589]

The index0-out.go test FAILs on Solaris (SPARC and x86, 32 and 64-bit),
as well as several others:

FAIL: ./index0-out.go execution,  -O0 -g -fno-var-tracking-assignments

The test SEGVs because it tries a stack acess way beyond the stack
area.  As Ian analyzed in the PR, the testcase currently requires
split-stack support, so this patch requires just that.

Tested on i386-pc-solaris2.11 and sparc-sun-solaris2.11.

2024-06-05  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	gcc/testsuite:
	PR go/87589
	* go.test/go-test.exp (go-gc-tests): Require split-stack support
	for index0.go.