Use large-model addressing for calls when in non-PIC mode.

The main use for non-PIC code at present is JIT code, and JIT code can
live anywhere in memory and reference other symbols defined anywhere in
memory, so it needs to use the "large" code model.

func_addr and globalsym_addr instructions were already using `movabs`
to support arbitrary 64-bit addresses, so this just makes calls be
legalized to support arbitrary 64-bit addresses also.

cranelift/filetests/isa/intel/prologue-epilogue.cton

@@ -1,6 +1,7 @@
 test compile
 set is_64bit
 set is_compressed
+set is_pic
 isa intel haswell
 
 ; An empty function.