testsuite: Fix recently added ipa testcases [PR93763]

testsuite: Fix recently added ipa testcases [PR93763]

Seems the test has been badly reduced (if the original doesn't emit
warnings, it is always better in the reduction script avoid introducing new
ones).
Also, the g++.dg/ipa/ test fails with -std=c++98 because it is written in
C++11.

2020-02-25  Jakub Jelinek  <jakub@redhat.com>

	PR ipa/93763
	* gcc.dg/ipa/pr93763.c: Adjust the test so that it compiles without
	warnings and still ICEs before the ipa-cp.c fix.
	* g++.dg/ipa/pr93763.C: Require c++11 effective target.