testsuite: Tweak check-function-bodies interface

testsuite: Tweak check-function-bodies interface

In g:2171a9207f51bc486ed9c502cb4da706f594615e I'd tried to fix
various ILP32 testsuite failures by restricting some tests to LP64.
Unfortunately, I messed up the check-function-bodies syntax and passed
the target selector as the "option" parameter, which had the effect of
disabling the tests for both ILP32 and LP64.

The fix ought to have been to add "" as the option parameter.  However,
check-function-bodies wasn't treating "" in the same way as an omitted
argument.  The easiest fix seemed to be turn the argument into a list of
options, which also makes the interface a bit more general.

Having done that, it seemed a good idea to check for things that look
like target/xfail selectors, so that the mistake isn't silent next time.

2020-04-09  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* doc/sourcebuild.texi (check-function-bodies): Treat the third
	parameter as a list of option regexps and require each regexp
	to match.

gcc/testsuite/
	* lib/scanasm.exp (check-function-bodies): Treat the third
	parameter as a list of option regexps and require each regexp
	to match.  Check for cases in which a target/xfail selector
	was mistakenly passed to the options argument.
	* gcc.target/aarch64/sve/pcs/args_1.c: Add an empty options list
	to the invocation of check-function-bodies.
	* gcc.target/aarch64/sve/pcs/args_2.c: Likewise.
	* gcc.target/aarch64/sve/pcs/args_3.c: Likewise.
	* gcc.target/aarch64/sve/pcs/args_4.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_1.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_1_1024.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_1_128.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_1_2048.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_1_256.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_1_512.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_2.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_3.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_4.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_4_1024.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_4_128.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_4_2048.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_4_256.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_4_512.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_5.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_5_1024.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_5_128.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_5_2048.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_5_256.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_5_512.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_6.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_6_1024.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_6_128.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_6_2048.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_6_256.c: Likewise.
	* gcc.target/aarch64/sve/pcs/return_6_512.c: Likewise.
	* gcc.target/aarch64/sve/pcs/saves_2_be_nowrap.c: Likewise.
	* gcc.target/aarch64/sve/pcs/saves_2_be_wrap.c: Likewise.
	* gcc.target/aarch64/sve/pcs/saves_2_le_nowrap.c: Likewise.
	* gcc.target/aarch64/sve/pcs/saves_2_le_wrap.c: Likewise.
	* gcc.target/aarch64/sve/pcs/saves_3.c: Likewise.
	* gcc.target/aarch64/sve/pcs/saves_4_be.c: Likewise.
	* gcc.target/aarch64/sve/pcs/saves_4_le.c: Likewise.
	* gcc.target/aarch64/sve/pcs/stack_clash_2_128.c: Likewise.
	* gcc.target/aarch64/sve/pcs/varargs_1.c: Likewise.
	* gcc.target/aarch64/sve/pcs/varargs_2_f16.c: Likewise.
	* gcc.target/aarch64/sve/pcs/varargs_2_f32.c: Likewise.
	* gcc.target/aarch64/sve/pcs/varargs_2_f64.c: Likewise.
	* gcc.target/aarch64/sve/pcs/varargs_2_s16.c: Likewise.
	* gcc.target/aarch64/sve/pcs/varargs_2_s32.c: Likewise.
	* gcc.target/aarch64/sve/pcs/varargs_2_s64.c: Likewise.
	* gcc.target/aarch64/sve/pcs/varargs_2_s8.c: Likewise.
	* gcc.target/aarch64/sve/pcs/varargs_2_u16.c: Likewise.
	* gcc.target/aarch64/sve/pcs/varargs_2_u32.c: Likewise.
	* gcc.target/aarch64/sve/pcs/varargs_2_u64.c: Likewise.
	* gcc.target/aarch64/sve/pcs/varargs_2_u8.c: Likewise.