gold: Remove the circular IFUNC dependency in ifuncmain6pie

On Fedora 33 x86-64 with glibc 2.32-3, ifuncmain6pie failed with:

./ifuncmain6pie: IFUNC symbol 'foo' referenced in './ifuncmod6.so' is defined in the executable and creates an unsatisfiable circular dependency.
FAIL ifuncmain6pie (exit status: 127)

Remove non-JUMP_SLOT relocations against foo in ifuncmod6.so, which
trigger the circular IFUNC dependency.

	* testsuite/ifuncmain6pie.c: Remove non-JUMP_SLOT relocations
	against foo in ifuncmod6.so.
	* testsuite/ifuncmod6.c: Likewise.

(cherry picked from commit 25294ff0)