Tests: Add symbols to FortranModules static libraries

When GNU `ar` creates an archive with no symbols it has only an
empty header but no string table.  On Solaris the OS-provided `ld`
fails in this case:

    ld: elf error: file libfoo.a: elf_getarsym

Update our test to actually provide symbols from its archives.

Tests/FortranModules/Library/a.f90

@@ -1,3 +1,6 @@
 MODULE libraryModuleA
         USE libraryModuleB
+CONTAINS
+        SUBROUTINE libA
+        END SUBROUTINE
 END MODULE

Tests/FortranModules/Library/b.f90

@@ -1,2 +1,5 @@
 MODULE libraryModuleB
+CONTAINS
+        SUBROUTINE libB
+        END SUBROUTINE
 END MODULE

Tests/FortranModules/Subdir/subdir.f90

@@ -1,2 +1,5 @@
 MODULE subdirModuleA
+CONTAINS
+        SUBROUTINE subdirLibA
+        END SUBROUTINE
 END MODULE