testsuite: Adjust patchable_function tests for mmix.

testsuite: Adjust patchable_function tests for mmix.

There's no reason anyone would want to use the "patchable function"
feature for MMIX and also no reason to exclude those tests.  For MMIX,
the NOP equivalent is SWYM ("swymming" is a healthy exercise).
Text-wise, making the tests pass by adjusting the regexp, is shorter,
and it seems unlikely to both appear as a mnemonic for other targets
*and* being emitted in uppercase.

gcc/testsuite:

	* c-c++-common/patchable_function_entry-decl.c,
	c-c++-common/patchable_function_entry-default.c,
	c-c++-common/patchable_function_entry-definition.c: Adjust for mmix.