[gdb/testsuite] Use MACRO_AT_{func,range}

[gdb/testsuite] Use MACRO_AT_{func,range}

Use dwarf assembly procs MACRO_AT_func and MACRO_AT_range in test-cases where
that's appropriate.

Tested on x86_64-linux.

gdb/testsuite/ChangeLog:

2020-07-17  Tom de Vries  <tdevries@suse.de>

	* gdb.dlang/circular.c (found): Use found_label as label name.
	* gdb.dwarf2/arr-subrange.c (main): Use main_label as label name.
	* gdb.dwarf2/comp-unit-lang.c (func): Use func_label as label name.
	* gdb.dlang/circular.exp: Use MACRO_AT_func and MACRO_AT_range.
	* gdb.dwarf2/ada-linkage-name.exp: Same.
	* gdb.dwarf2/arr-subrange.exp: Same.
	* gdb.dwarf2/atomic-type.exp: Same.
	* gdb.dwarf2/comp-unit-lang.exp: Same.
	* gdb.dwarf2/cpp-linkage-name.exp: Same.
	* gdb.dwarf2/dw2-bad-mips-linkage-name.exp: Same.
	* gdb.dwarf2/dw2-lexical-block-bare.exp: Same.
	* gdb.dwarf2/dw2-regno-invalid.exp: Same.
	* gdb.dwarf2/implptr-64bit.exp: Same.
	* gdb.dwarf2/imported-unit-abstract-const-value.exp: Same.
	* gdb.dwarf2/imported-unit-runto-main.exp: Same.
	* gdb.dwarf2/imported-unit.exp: Same.
	* gdb.dwarf2/main-subprogram.exp: Same.
	* gdb.dwarf2/missing-type-name.exp: Same.
	* gdb.dwarf2/nonvar-access.exp: Same.
	* gdb.dwarf2/struct-with-sig.exp: Same.
	* gdb.dwarf2/typedef-void-finish.exp: Same.
	* gdb.dwarf2/void-type.exp: Same.