Fix -freorder-blocks-and-partition glitch with Windows SEH (continued)

Fix -freorder-blocks-and-partition glitch with Windows SEH (continued)

This fixes a thinko in the fix for the -freorder-blocks-and-partition
glitch with SEH on 64-bit Windows:
  https://gcc.gnu.org/pipermail/gcc-patches/2021-February/565208.html

Even if no exceptions are active, e.g. in C, we need to consider calls.

gcc/
	PR target/103274
	* config/i386/i386.c (ix86_output_call_insn): Beef up comment about
	nops emitted with SEH.
	* config/i386/winnt.c (i386_pe_seh_unwind_emit): When switching to
	the cold section, emit a nop before the directive if the previous
	active instruction is a call.