[Ada] Reset internal flags for -gnatD and -gnatG

[Pierre-Marie de Rodat via Gcc-patches]

This resets the internal flags associated with the -gnatD and -gnatG
switches once the generated code is printed, so that it does not end
up being printed twice in case something goes wrong after this point.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

        * sprint.adb (Source_Dump): Set both Print_Generated_Code and
        Debug_Generated_Code to False at the end.
diff --git a/gcc/ada/sprint.adb b/gcc/ada/sprint.adb
--- a/gcc/ada/sprint.adb
+++ b/gcc/ada/sprint.adb
@@ -673,6 +673,11 @@ package body Sprint is
             end if;
          end loop;
       end if;
+
+      --  See above for the rationale, but we cannot do it earlier for them
+
+      Print_Generated_Code := False;
+      Debug_Generated_Code := False;
    end Source_Dump;
 
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