gccrs: Add test case showing method resolution with const-generics

gcc/testsuite/ChangeLog:

	* rust/execute/torture/const-generics-1.rs: New test.

Signed-off-by: Philip Herron <[email protected]>

Author: philberty

gcc/testsuite/rust/execute/torture/const-generics-1.rs

@@ -0,0 +1,24 @@
+#[lang = "sized"]
+trait Sized {}
+
+struct Foo<const N: usize>;
+
+impl Foo<1> {
+    fn call(&self) -> i32 {
+        10
+    }
+}
+
+impl Foo<2> {
+    fn call(&self) -> i32 {
+        20
+    }
+}
+
+fn main() -> i32 {
+    let a = Foo::<1> {};
+    let b = Foo::<2> {};
+    let aa = a.call();
+    let bb = b.call();
+    bb - aa - 10
+}