RISC-V: Robostify testcase pr113112-1.c

The redudant dump check is fragile and easily changed, not necessary.

Tested on both RV32/RV64 no regression.

Remove it and committed.

gcc/testsuite/ChangeLog:

	* gcc.dg/vect/costmodel/riscv/rvv/pr113112-1.c: Remove redundant checks.