fortran: cleanup duplicate tests for c_f_pointer_shape_driver

fortran: cleanup duplicate tests for c_f_pointer_shape_driver

tests_2_driver and tests_4_driver are identical, and tests_4_driver is not used
at all. This patch clean this up, and format the driver with gcc style.

gcc/testsuite/ChangeLog:

	* gfortran.dg/c_f_pointer_shape_tests_2.f03: Use the new driver.
	* gfortran.dg/c_f_pointer_shape_tests_4.f03: Ditto.
	* gfortran.dg/c_f_pointer_shape_tests_4_driver.c: Removed.
	* gfortran.dg/c_f_pointer_shape_tests_2_driver.c: Renamed to ...
	* gfortran.dg/c_f_pointer_shape_tests_driver.c: ... this; format
	with gcc style.