This fix keeps the section with the highest alignment when folding sections with ICF.
PR gold/17704
* icf.cc (match_sections): Add new parameter section_addraligns.
Check section alignment and keep the section with the strictest
alignment.
(find_identical_sections): New local variable section_addraligns.
Store each section's alignment.
* testsuite/pr17704a_test.s: New file.
* testsuite/Makefile.am (pr17704a_test): New test.
* testsuite/Makefile.in: Regenerate.