aarch64: Rename svpext to svpext_lane [PR116371]

aarch64: Rename svpext to svpext_lane [PR116371]

When implementing the SME2 ACLE, I somehow missed off the _lane
suffix on svpext.

gcc/
	PR target/116371
	* config/aarch64/aarch64-sve-builtins-sve2.h (svpext): Rename to...
	(svpext_lane): ...this.
	* config/aarch64/aarch64-sve-builtins-sve2.cc (svpext_impl): Rename
	to...
	(svpext_lane_impl): ...this and update instantiation accordingly.
	* config/aarch64/aarch64-sve-builtins-sve2.def (svpext): Rename to...
	(svpext_lane): ...this.

gcc/testsuite/
	PR target/116371
	* gcc.target/aarch64/sme2/acle-asm/pext_c16.c,
	gcc.target/aarch64/sme2/acle-asm/pext_c16_x2.c,
	gcc.target/aarch64/sme2/acle-asm/pext_c32.c,
	gcc.target/aarch64/sme2/acle-asm/pext_c32_x2.c,
	gcc.target/aarch64/sme2/acle-asm/pext_c64.c,
	gcc.target/aarch64/sme2/acle-asm/pext_c64_x2.c,
	gcc.target/aarch64/sme2/acle-asm/pext_c8.c,
	gcc.target/aarch64/sme2/acle-asm/pext_c8_x2.c: Replace with...
	* gcc.target/aarch64/sme2/acle-asm/pext_lane_c16.c,
	gcc.target/aarch64/sme2/acle-asm/pext_lane_c16_x2.c,
	gcc.target/aarch64/sme2/acle-asm/pext_lane_c32.c,
	gcc.target/aarch64/sme2/acle-asm/pext_lane_c32_x2.c,
	gcc.target/aarch64/sme2/acle-asm/pext_lane_c64.c,
	gcc.target/aarch64/sme2/acle-asm/pext_lane_c64_x2.c,
	gcc.target/aarch64/sme2/acle-asm/pext_lane_c8.c,
	gcc.target/aarch64/sme2/acle-asm/pext_lane_c8_x2.c: ...these new tests,
	testing for svpext_lane instead of svpext.