Adjust testcase for --target_board='unix{-m64\ -march=cascadelake}'

Adjust testcase for --target_board='unix{-m64\ -march=cascadelake}'

Change scan-assembler from "\tucomisd" to "\t\[v\]?ucomisd".

gcc/testsuite/ChangeLog:

	PR target/103973
	* g++.target/i386/pr103973-1.C: Change scan-assembler from
	"\tucomisd" to "\t\[v\]?ucomisd".
	* g++.target/i386/pr103973-11.C: Ditto.
	* g++.target/i386/pr103973-13.C: Ditto.
	* g++.target/i386/pr103973-15.C: Ditto.
	* g++.target/i386/pr103973-3.C: Ditto.
	* g++.target/i386/pr103973-5.C: Ditto.
	* g++.target/i386/pr103973-7.C: Ditto.
	* g++.target/i386/pr103973-9.C: Ditto.
	* gcc.target/i386/pr103973-1.c: Ditto.
	* gcc.target/i386/pr103973-11.c: Ditto.
	* gcc.target/i386/pr103973-13.c: Ditto.
	* gcc.target/i386/pr103973-15.c: Ditto.
	* gcc.target/i386/pr103973-3.c: Ditto.
	* gcc.target/i386/pr103973-5.c: Ditto.
	* gcc.target/i386/pr103973-7.c: Ditto.
	* gcc.target/i386/pr103973-9.c: Ditto.