Fortran: check for non-optional spaces between adjacent keywords

Fortran: check for non-optional spaces between adjacent keywords

In free format, spaces between adjacent keywords are not optional except
when a combination is explicitly listed (e.g. F2018: table 6.2).  The
following combinations thus require separating blanks: CHANGE TEAM,
ERROR STOP, EVENT POST, EVENT WAIT, FAIL IMAGE, FORM TEAM, SELECT RANK,
SYNC ALL, SYNC IMAGES, SYNC MEMORY, SYNC TEAM, TYPE IS.

gcc/fortran/ChangeLog:

	PR fortran/105501
	* match.cc (gfc_match_if): Adjust patterns used for matching.
	(gfc_match_select_rank): Likewise.
	* parse.cc (decode_statement): Likewise.

gcc/testsuite/ChangeLog:

	PR fortran/105501
	* gfortran.dg/pr105501.f90: New test.