AVR: Rename test case to PR number.

	PR rtl-optimization/117191
gcc/testsuite/
	* gcc.target/avr/torture/pr117189.c: Rename to...
	* gcc.target/avr/torture/pr117191.c: ...this.

diff --git a/gcc/testsuite/gcc.target/avr/torture/pr117189.c b/gcc/testsuite/gcc.target/avr/torture/pr117191.c
similarity index 100%
rename from gcc/testsuite/gcc.target/avr/torture/pr117189.c
rename to gcc/testsuite/gcc.target/avr/torture/pr117191.c