testsuite: Update scan-lto-assembler

scan-lto-assembler was looking for the old dump names instead of
the new ones.  There are only two uses of this:

    gcc.target/nios2/custom-fp-lto.c
    gcc.target/aarch64/pr70044.c

Both of them use single source files, so I think they both want
the same behaviour.

gcc/testsuite/
	* lib/scanasm.exp (scan-lto-assembler): Update expected name
	of dump file.

gcc/testsuite/lib/scanasm.exp

@@ -754,7 +754,7 @@ proc scan-lto-assembler { args } {
     set testcase [testname-for-summary]
     # The name might include a list of options; extract the file name.
     set filename [lindex $testcase 0]
-    set output_file "[file rootname [file tail $filename]].exe.ltrans0.s"
+    set output_file "[file rootname [file tail $filename]].ltrans0.ltrans.s"
     verbose "output_file: $output_file"
     dg-scan "scan-lto-assembler" 1 $testcase $output_file $args
 }