libsframe: testsuite: reduce usage of magic numbers from encode-1.c

Previously, some of the libsframe tests were updated to reduce the usage
of magic numbers.  This patch makes encode-1.c follow similar coding
style as other tests, reducing the number of magic constants.

libsframe/testsuite/
	* libsframe.encode/encode-1.c: Avoid magic numbers.
1 file changed