testsuite: remove SPE tests.

testsuite: remove SPE tests.

SPE support was removed from the "rs6000" port.  This patch removes some
left-over SPE-specific testcases from the gcc.target/powerpc directory.

gcc/testsuite/ChangeLog

2020-06-30  David Edelsohn  <dje.gcc@gmail.com>

	* gcc.target/powerpc/ppc-spe.c: Delete.
	* gcc.target/powerpc/ppc-spe64-1.c: Delete.
	* gcc.target/powerpc/pr60102.c: Delete.
	* gcc.target/powerpc/pr60158.c: Delete.
	* gcc.target/powerpc/pr60735.c: Delete.
	* gcc.target/powerpc/pr78458.c: Delete.
	* gcc.target/powerpc/pr80343.c: Delete.
	* gcc.target/powerpc/spe-evmerge.c: Delete.
	* gcc.target/powerpc/spe-small-data-1.c: Delete.
	* gcc.target/powerpc/spe-small-data-2.c: Delete.
	* gcc.target/powerpc/spe-unwind-1.c: Delete.
	* gcc.target/powerpc/spe-vector-memcpy.c: Delete.
	* gcc.target/powerpc/spe-vector-memset.c: Delete.
	* gcc.target/powerpc/spe1.c: Delete.