gfortran testsuite: Remove unit-files in files having open-statements, PR116701

PR testsuite/116701 shows that left-behind files from
unnamed gfortran open statements (named unit.N, where N =
unit number) can interfere with the result of a subsequent
run.  While that's unlikely to happen for a "real" fortran
target or a test with a deleting close-statement, test-cases
should not rely on previous test-cases passing and not
execute along different execution paths depending on earlier
runs, even if the difference is benevolent.

Most but not all fortran test-cases go through
gfortran-dg-runtest (gfortran.dg) or fortran-torture-execute
(gfortran.fortran-torture).  However, the exceptions, with
more complex framework and call-chains, either don't run or
don't have open-statements, so a more complex solution
doesn't seem worthwhile.  If test-cases with open-statements
are added later to those parts of the test-suite, calls to
fortran-delete-unit-files at the right spot may be added or
worst case, "manual" cleanup-calls added, like:
! { dg-final { remote_file target delete "fort.10" } }
Put the new proc in fortran-modules.exp since that's where other
common fortran-testsuite dejagnu-library functions are located.

	PR testsuite/116701
	* lib/fortran-modules.exp (fortran-delete-unit-files): New proc.
	* lib/gfortran-dg.exp (gfortran-dg-runtest): Call
	fortran-delete-unit-files after executing test.
	* lib/fortran-torture.exp (fortran-torture-execute): Ditto.

gcc/testsuite/lib/fortran-modules.exp

@@ -172,3 +172,24 @@ proc igrep { args } {
     }
     return $grep_out
 }
+
+# If the code has any "open" statements for numbered units, make sure
+# no corresponding output file remains.  Redundant remove operations
+# are ok, but duplicate removals look sloppy, so track for uniqueness.
+proc fortran-delete-unit-files { src } {  
+    set openpat {open *\( *(?:unit *= *)?([0-9]+)}
+    set openmatches [igrep $src $openpat]
+    if {![string match "" $openmatches]} {
+	# verbose -log "Found \"$openmatches\""
+	set deleted_units {}
+	foreach openmatch $openmatches {
+	    regexp -nocase -- "$openpat" $openmatch match unit
+	    if {[lsearch $deleted_units $unit] < 0} {
+		set rmfile "fort.$unit"
+		verbose -log "Deleting $rmfile"
+		remote_file target delete "fort.$unit"
+		lappend deleted_units $unit
+	    }
+	}
+    }
+}

gcc/testsuite/lib/fortran-torture.exp

@@ -332,6 +332,8 @@ proc fortran-torture-execute { src } {
 	    catch { remote_file build delete $executable }
         }
 	$status "$testcase execution, $option"
+
+	fortran-delete-unit-files $src
     }
     cleanup-modules ""
 }

gcc/testsuite/lib/gfortran-dg.exp

@@ -160,6 +160,7 @@ proc gfortran-dg-runtest { testcases flags default-extra-flags } {
 	foreach flags_t $option_list {
 	    verbose "Testing $nshort, $flags $flags_t" 1
 	    dg-test $test "$flags $flags_t" ${default-extra-flags}
+	    fortran-delete-unit-files $test
 	    cleanup-modules ""
 	}
     }