[testsuite] Scan final instead of asm in independent-cloneids-1.c

[testsuite] Scan final instead of asm in independent-cloneids-1.c

When running test-case gcc.dg/independent-cloneids-1.c for nvptx, we get:
...
FAIL: scan-assembler-times (?n)^_*bar[.$_]constprop[.$_]0: 1
FAIL: scan-assembler-times (?n)^_*bar[.$_]constprop[.$_]1: 1
FAIL: scan-assembler-times (?n)^_*bar[.$_]constprop[.$_]2: 1
FAIL: scan-assembler-times (?n)^_*foo[.$_]constprop[.$_]0: 1
FAIL: scan-assembler-times (?n)^_*foo[.$_]constprop[.$_]1: 1
FAIL: scan-assembler-times (?n)^_*foo[.$_]constprop[.$_]2: 1
...

The test expects to find something like:
...
bar.constprop.0:
...
but instead on nvptx we have:
...
.func (.param.u32 %value_out) bar$constprop$0
...

Fix this by rewriting the scans to use the final dump instead.

Tested on x86_64.

gcc/testsuite/ChangeLog:

2020-09-24  Tom de Vries  <tdevries@suse.de>

	* gcc.dg/independent-cloneids-1.c: Use scan-rtl-dump instead of
	scan-assembler.