i386: Fix up *<dwi>3_doubleword_mask [PR105911]

Another regression caused by my recent patch.

This time because define_insn_and_split only requires that the
constant mask is const_int_operand.  When it was only SImode,
that wasn't a problem, HImode neither, but for DImode if we need
to and the shift count we might run into a problem that it isn't
a representable signed 32-bit immediate.

But, we don't really care about the upper bits of the mask, so
we can just mask the CONST_INT with the mode mask.

2022-06-13  Jakub Jelinek  <jakub@redhat.com>

	PR target/105911
	* config/i386/i386.md (*ashl<dwi>3_doubleword_mask,
	*<insn><dwi>3_doubleword_mask): Use operands[3] masked with
	(<MODE_SIZE> * BITS_PER_UNIT) - 1 as AND operand instead of
	operands[3] unmodified.

	* gcc.dg/pr105911.c: New test.