port-sparc/53277: Many ubsan tests fail on sparc

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         53277
>Category:       port-sparc
>Synopsis:       Many ubsan tests fail on sparc
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    port-sparc-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri May 11 15:50:00 +0000 2018
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date >= 2018.05.02.18.46.05
>Organization:

>Environment:
System: NetBSD guava.gson.org 7.1.1 NetBSD 7.1.1 (GENERIC.201712222334Z) amd64
Architecture: sparc
Machine: sparc
>Description:

The number of failing test cases on the sparc testbed jumped from 11 to 50
with the following commits:

  2018.05.02.18.46.05 kamil src/distrib/sets/lists/tests/mi 1.782
  2018.05.02.18.46.05 kamil src/tests/usr.bin/c++/Makefile 1.9
  2018.05.02.18.46.05 kamil src/tests/usr.bin/c++/t_ubsan_int_add_overflow.sh 1.1
  2018.05.02.18.46.05 kamil src/tests/usr.bin/c++/t_ubsan_int_divzero.sh 1.1
  2018.05.02.18.46.05 kamil src/tests/usr.bin/c++/t_ubsan_int_neg_overflow.sh 1.1
  2018.05.02.18.46.05 kamil src/tests/usr.bin/c++/t_ubsan_int_sub_overflow.sh 1.1
  2018.05.02.18.46.05 kamil src/tests/usr.bin/c++/t_ubsan_vla_out_of_bounds.sh 1.1
  2018.05.02.18.46.05 kamil src/tests/usr.bin/cc/Makefile 1.4
  2018.05.02.18.46.05 kamil src/tests/usr.bin/cc/t_ubsan_int_add_overflow.sh 1.1
  2018.05.02.18.46.05 kamil src/tests/usr.bin/cc/t_ubsan_int_divzero.sh 1.1
  2018.05.02.18.46.05 kamil src/tests/usr.bin/cc/t_ubsan_int_neg_overflow.sh 1.1
  2018.05.02.18.46.05 kamil src/tests/usr.bin/cc/t_ubsan_int_sub_overflow.sh 1.1
  2018.05.02.18.46.05 kamil src/tests/usr.bin/cc/t_ubsan_vla_out_of_bounds.sh 1.1

>How-To-Repeat:

Inspect the test reports at

  http://releng.netbsd.org/b5reports/sparc/commits-2018.05.html#2018.05.02.18.46.05

>Fix: