re PR target/28966 (-maltivec -m32 causes the stack to be saved and restored even though there is no need for it)

gcc/
	PR target/28966
	PR target/29248
	* reload1.c (reload): Realign stack after it changes size.
gcc/testsuite/
	PR target/28966
	PR target/29248
	* gcc.dg/rs6000-leaf.c: New.

From-SVN: r120102