Units(Fortran): add a case with mixed (free and fixed forms) input files

Close #3529.
Taken from examples reported by @mjaj as part of the issue report #3529.

Author: masatake

Units/parser-fortran.r/multi-input-fixed-then-free.d/args.ctags

@@ -0,0 +1 @@
+--sort=no

Units/parser-fortran.r/multi-input-fixed-then-free.d/expected.tags

@@ -0,0 +1,4 @@
+p1	input.f	/^      program p1$/;"	p
+s	input.f	/^      character*5  s$/;"	v	program:p1
+r	input.f	/^      chara/;"	v	program:p1
+s1	input-0.f90	/^subroutine s1$/;"	s

Units/parser-fortran.r/multi-input-fixed-then-free.d/input-0.f90

@@ -0,0 +1,7 @@
+subroutine s1
+real            :: a,b,c,d
+if (a .eq. b .and. &
+     c. eq. d) then
+   a=0
+endif
+end

Units/parser-fortran.r/multi-input-fixed-then-free.d/input.f

@@ -0,0 +1,6 @@
+      program p1
+      character*5  s
+c
+      character*5  r
+      r="abcde"
+      end

Units/parser-fortran.r/multi-input-free-then-fixed.d/args.ctags

@@ -0,0 +1 @@
+--sort=no

Units/parser-fortran.r/multi-input-free-then-fixed.d/expected.tags

@@ -0,0 +1,4 @@
+s1	input.f90	/^subroutine s1$/;"	s
+p1	input-0.f	/^      program p1$/;"	p
+s	input-0.f	/^      character*5  s$/;"	v	program:p1
+r	input-0.f	/^      chara/;"	v	program:p1

Units/parser-fortran.r/multi-input-free-then-fixed.d/input-0.f

@@ -0,0 +1,6 @@
+      program p1
+      character*5  s
+c
+      character*5  r
+      r="abcde"
+      end

Units/parser-fortran.r/multi-input-free-then-fixed.d/input.f90

@@ -0,0 +1,7 @@
+subroutine s1
+real            :: a,b,c,d
+if (a .eq. b .and. &
+     c. eq. d) then
+   a=0
+endif
+end