RISC-V/testsuite: Add branched cases for FP NE cond-move operations

RISC-V/testsuite: Add branched cases for FP NE cond-move operations

Verify, for generic, Ventana and Zicond targets and the floating-point
NE conditional-move operation, that if-conversion does *not* trigger at
the respective sufficiently low `-mbranch-cost=' settings that make
original branched code sequences cheaper than their branchless
equivalents if-conversion would emit.

	gcc/testsuite/
	* gcc.target/riscv/movdibfeq-ventana.c: New test.
	* gcc.target/riscv/movdibfeq-zicond.c: New test.
	* gcc.target/riscv/movdibfeq.c: New test.
	* gcc.target/riscv/movsibfeq-ventana.c: New test.
	* gcc.target/riscv/movsibfeq-zicond.c: New test.
	* gcc.target/riscv/movsibfeq.c: New test.