Add x64 support for remaining int-to-int extend simd instructions

Adds remaming support for int to int extend simd instructions.
Specifically adds support for remaining I32x4->I64x2 instructions

build.rs

@@ -192,7 +192,6 @@ fn x64_should_panic(testsuite: &str, testname: &str, strategy: &str) -> bool {
     match (testsuite, testname) {
         ("simd", "simd_i16x8_extadd_pairwise_i8x16") => return true,
         ("simd", "simd_i32x4_extadd_pairwise_i16x8") => return true,
-        ("simd", "simd_int_to_int_extend") => return true,
         ("simd", _) => return false,
         _ => {}
     }