[Ada] Fix conformance errors and erroneous code

gcc/ada/

	* contracts.adb, einfo-utils.adb, einfo-utils.ads, exp_ch7.adb,
	exp_ch9.adb, exp_disp.adb, exp_prag.adb, exp_smem.adb,
	exp_util.adb, freeze.adb, sem_aggr.adb, sem_attr.adb,
	sem_ch8.adb, sem_prag.ads, sem_util.adb, sem_util.ads: Fix
	conformance errors.
	* errout.adb, erroutc.adb: Remove pragmas Suppress.
	* err_vars.ads: Initialize variables that were previously being
	read uninitialized.
19 files changed