[libgomp, testsuite, openacc] Remove -foffload=-w in reduction-[1-5].c

[libgomp, testsuite, openacc] Remove -foffload=-w in reduction-[1-5].c

Before the commit "[libgomp, testsuite, openacc] Don't use const int for
dimensions", the "const int" construct was used to set launch dimensions in
reductions-[1-5].c.  In the case of -xc -O0, the const int is implemented as a
variable by the C front-end.  Consequently, the nvptx back-end generated
warnings that vector_length was overridden to be hard-coded, rather than left to
be set at runtime.  The test-cases silenced these warnings by switching off all
warnings in the accelerator compiler using "-foffload=-w".

Given that no warnings occur anymore, remove the "-foffload=-w" setting.

2019-01-11  Tom de Vries  <tdevries@suse.de>

	* testsuite/libgomp.oacc-c-c++-common/reduction-1.c: Remove
	-foffload=-w.
	* testsuite/libgomp.oacc-c-c++-common/reduction-2.c: Same.
	* testsuite/libgomp.oacc-c-c++-common/reduction-3.c: Same.
	* testsuite/libgomp.oacc-c-c++-common/reduction-4.c: Same.
	* testsuite/libgomp.oacc-c-c++-common/reduction-5.c: Same.

From-SVN: r267836