if-to-switch: Don't skip the first condition bb when find_conditions in if-to-switch...

if-to-switch: Don't skip the first condition bb when find_conditions in if-to-switch [PR105740]

The if condition is at last of first bb, so side effect statement in first BB
doesn't matter, then the first if condition could also be folded to switch
table.

gcc/ChangeLog:

	PR target/105740
	* gimple-if-to-switch.cc (find_conditions): Don't skip the first
	condition bb.

gcc/testsuite/ChangeLog:

	PR target/105740
	* gcc.dg/tree-ssa/if-to-switch-11.c: New test.

Signed-off-by: Xionghu Luo <xionghuluo@tencent.com>