gdb/testsuite/

gdb/testsuite/
	* gdb.dwarf2/dw2-ranges.S: Rename to ...
	* gdb.dwarf2/dw2-ranges.c: ... here, convert it to C.
	* gdb.dwarf2/dw2-ranges.exp: Skip the testcase on !$gcc_compiled.
	Rename srcfile, srcfile2 and srcfile3, new asmfile, asmfile2 and
	asmfile3.  Comment the STABS (#3) file compilation.  Compile
	everything through assembler.  Provide KFAIL for symtab/12497.
	* gdb.dwarf2/dw2-ranges2.S: Rename to ...
	* gdb.dwarf2/dw2-ranges2.c: ... here, convert it to C.
	* gdb.dwarf2/dw2-ranges3.S: Rename to ...
	* gdb.dwarf2/dw2-ranges3.c: ... here, convert it to C.