Darwin, c++, testsuite - adjust alignas4.C for Darwin's asm syntax.

Darwin, c++, testsuite - adjust alignas4.C for Darwin's asm syntax.

Darwin produces aligned zerofill directives for the objects represented.
We can scan for these using "lp64" and "ilp32" to catch operation on both
X86 and PowerPC ports (the test is for the alignment which is the trailing
value in the zerofill directive, as a power of two).

gcc/testsuite/ChangeLog:

2019-06-06  Iain Sandoe  <iain@sandoe.co.uk>

	* g++.dg/cpp0x/alignas4.C: Amend test to check for zerofill syntax
	on Darwin.

From-SVN: r272018