target-supports.exp: Add check for "inf" effective target keyword.

target-supports.exp: Add check for "inf" effective target keyword.

	* lib/target-supports.exp: Add check for "inf" effective target
	keyword.
	* gcc.dg/builtins-44.c: Skip if no infinite support.
	* gcc.dg/builtins-45.c: Ditto.
	* gcc.dg/torture/builtin-complex-1.c: Ditto.
	* gcc.dg/torture/builtin-cproj-1.c: Ditto.
	* gcc.dg/torture/builtin-frexp-1.c: Ditto.
	* gcc.dg/torture/builtin-ldexp-1.c: Ditto.
	* gcc.dg/torture/builtin-logb-1.c: Ditto.
	* gcc.dg/torture/builtin-math-2.c: Ditto.
	* gcc.dg/torture/builtin-math-5.c: Ditto.
	* gcc.dg/torture/builtin-math-7.c: Ditto.
	* gcc.dg/torture/builtin-modf-1.c: Ditto.
	* gcc.dg/torture/type-generic-1.c: Ditto.

From-SVN: r265816