arm: unified syntax for libgcc when built with -Os [PR94220]

arm: unified syntax for libgcc when built with -Os [PR94220]

The recent patch to convert all thumb1 code in libgcc to unified syntax
ommitted the conditional code that is used only when building the library
for minimal size.  This patch fixes this case.

I've also fixed the COND macro so that a single definition is always used
that is for unified syntax.  This eliminates a warning that is now being
seen from the assembler when compiling the ieee fp support code.

	PR target/94220
	* config/arm/lib1funcs.asm (COND): Use a single definition for
	unified syntax.
	(aeabi_uidivmod): Unified syntax when optimizing Thumb for size.
	(aeabi_idivmod): Likewise.
	(divsi3_skip_div0_test): Likewise.