cfgrtl: Fix up fixup_partitions caused ICE [PR99085]

cfgrtl: Fix up fixup_partitions caused ICE [PR99085]

fixup_partitions sometimes changes some basic blocks from hot partition to
cold partition, in particular if after unreachable block removal or other
optimizations a hot partition block is dominated by cold partition block(s).
It fixes up the edges and jumps on those edges, but when after reorder
blocks and in rtl (non-cfglayout) mode that is clearly not enough, because
it keeps the block order the same and so we can end up with more than
1 hot/cold section transition in the same function.

So, this patch fixes that up too.

2021-03-03  Jakub Jelinek  <jakub@redhat.com>

	PR target/99085
	* cfgrtl.c (fixup_partitions): When changing some bbs from hot to cold
	partitions, if in non-layout mode after reorder_blocks also move
	affected blocks to ensure a single partition transition.

	* gcc.dg/graphite/pr99085.c: New test.

(cherry picked from commit 4ad5b1915d50cc39691487f58794d699c7900ace)