[utils] Fix force inlining compilation error with gcc on linux

[02131]   CC       libmonoruntimesgen_la-sgen-marksweep.lo
[02131] In file included from sgen-major-copy-object.h:35:0,
[02131]                  from sgen-marksweep.c:1128:
[02131] sgen-copy-object.h:38:1: warning: always_inline function might not be inlinable [-Wattributes]
[02131]  par_copy_object_no_checks (char *destination, MonoVTable *vt, void *obj, mword objsize, SgenGrayQueue *queue)
[02131]  ^
[02131] sgen-marksweep.c: In function 'par_copy_object_no_checks':
[02131] sgen-copy-object.h:38:1: error: function 'par_copy_object_no_checks' can never be copied because it saves address of local label in a static variable
[02131] make[3]: *** [libmonoruntimesgen_la-sgen-marksweep.lo] Error 1
[02131] make[3]: Leaving directory `/root/rpmbuild/BUILD/mono-3.10.1/mono/metadata'
[02131] make[2]: *** [all-recursive] Error 1
[02131] make[2]: Leaving directory `/root/rpmbuild/BUILD/mono-3.10.1/mono'
[02131] make[1]: *** [all-recursive] Error 1
[02131] make[1]: Leaving directory `/root/rpmbuild/BUILD/mono-3.10.1'
[02131] make: *** [all] Error 2
[02131] error: Bad exit status from /var/tmp/rpm-tmp.YxcUOE (%build)