ada: Inline composite node kind AST queries

ada: Inline composite node kind AST queries

Queries that ultimately examine the same field of an AST
node (e.g. Nkind) are visibly more efficient when inlined.

In particular, routines Is_Body_Or_Package_Declaration and Is_Body can
apparently be inlined into a single Nkind membership test.

This patch fixes some of the performance lost with the recent changes,
which increased the number of calls to Is_Body_Or_Package_Declaration
(as it is typically used to prevent AST search from climbing too far).
However, it should be generally beneficial to inline routines like this.

gcc/ada/

	* sem_aux.ads (Is_Body): Annotate with Inline.
	* sem_util.ads (Is_Body_Or_Package_Declaration): Likewise.