RISC-V: Make xtheadcondmov-indirect tests robust against instruction reordering

Fixes: c1bc7513 ("RISC-V: const: hide mvconst splitter from IRA")

A recent change broke the xtheadcondmov-indirect tests, because the order of
emitted instructions changed. Since the test is too strict when testing for
a fixed instruction order, let's change the tests to simply count instruction,
like it is done for similar tests.

Reported-by: Patrick O'Neill <patrick@rivosinc.com>
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/xtheadcondmov-indirect.c: Make robust against
	instruction reordering.