Upgrade ACATS testsuite to latest ACATS 2.6

Upgrade ACATS testsuite to latest ACATS 2.6

This upgrades the ACATS tesuite present in ada/acats from 2.5 to latest 2.6,
removing 3 tests and adding 11 tests, some of them written very recently.

gcc/testsuite/ChangeLog:
	* ada/acats/support/acats25.lst: Delete.
	* ada/acats/support/acats26.lst: New file.
	* ada/acats/support/fcndecl.ada: Minor tweak.
	* ada/acats/support/impdef.a: Add commentary.
	* ada/acats/support/impdefg.a (Negative_Zero return): Simplify.
	* ada/acats/support/macro.dfs (TASK_STORAGE_SIZE): Bump.
	* ada/acats/support/repbody.ada: Upgrade to ACATS 2.6.
	* ada/acats/support/tctouch.ada: Likewise.
	* ada/acats/tests/c3/c352001.a: New file.
	* ada/acats/tests/c4/c433001.a: Correct error messages.
	* ada/acats/tests/c4/c453001.a: New file.
	* ada/acats/tests/c4/c45622a.ada: Delete.
	* ada/acats/tests/c4/c45624a.ada: Likewise.
	* ada/acats/tests/c4/c45624b.ada: Likewise.
	* ada/acats/tests/c4/c460013.a: New file.
	* ada/acats/tests/c4/c460014.a: Likewise.
	* ada/acats/tests/c6/c620001.a: Likewise.
	* ada/acats/tests/c6/c620002.a: Likewise.
	* ada/acats/tests/c7/c761006.a: Redo Unchecked_Deallocation case.
	* ada/acats/tests/c9/c96004a.ada: Adjust for Ada 2005.
	* ada/acats/tests/c9/c96007a.ada: Likewise.
	* ada/acats/tests/cb/cb41004.a: Adjust for AI95-0044.
	* ada/acats/tests/cc/cc3016f.ada: Minor tweak.
	* ada/acats/tests/cd/cd30011.a: New file.
	* ada/acats/tests/cd/cd30012.a: Likewise.
	* ada/acats/tests/cd/cd90001.a: Fix comparison.
	* ada/acats/tests/cxa/cxa3004.a: New file.
	* ada/acats/tests/cxa/cxa5013.a: Likewise.
	* ada/acats/tests/cxa/cxac005.a: Adjust for return-by-reference.
	* ada/acats/tests/cxb/cxb30061.am: New file.
	* ada/acats/tests/cxf/cxf2001.a: Fix failure message.