RISC-V: Fix incorrect folder for VRGATHERI16 test case

Put the test file to the incorrect folder, this patch would like to
fix it.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/intrisinc-vrgatherei16.c: Moved to...
	* gcc.target/riscv/rvv/base/intrisinc-vrgatherei16.c: ...here.

Signed-off-by: Pan Li <pan2.li@intel.com>
(cherry picked from commit 0574a19047fa66f26a38e79c1b9ae6a8207bba89)

diff --git a/gcc/testsuite/gcc.target/riscv/rvv/intrisinc-vrgatherei16.c b/gcc/testsuite/gcc.target/riscv/rvv/base/intrisinc-vrgatherei16.c
similarity index 100%
rename from gcc/testsuite/gcc.target/riscv/rvv/intrisinc-vrgatherei16.c
rename to gcc/testsuite/gcc.target/riscv/rvv/base/intrisinc-vrgatherei16.c