core_arch: disable assert_instr for pfalse

The implementation for this has the same behaviour as a `pfalse` but
doesn't currently emit one until an intrinsic is added to emit a
`zeroinitializer` for this.

Author: davidtwco

crates/core_arch/src/aarch64/sve/generated.rs

@@ -30819,7 +30819,6 @@ pub fn svorv_u64(pg: svbool_t, op: svuint64_t) -> u64 {
 #[inline(always)]
 #[target_feature(enable = "sve")]
 #[unstable(feature = "stdarch_aarch64_sve", issue = "145052")]
-#[cfg_attr(test, assert_instr(pfalse))]
 pub fn svpfalse_b() -> svbool_t {
     svdupq_n_b8(
         false, false, false, false, false, false, false, false, false, false, false, false, false,

crates/stdarch-gen-arm/spec/sve/aarch64.spec.yml

@@ -3611,7 +3611,9 @@ intrinsics:
     doc: Set all predicate elements to false
     arguments: []
     return_type: "svbool_t"
-    assert_instr: [pfalse]
+    # TODO: With current implementation, `pfalse` isn't generated, will need to add intrinsic to
+    # generate `zeroinitializer`
+    # assert_instr: [pfalse] 
     compose:
       - FnCall:
           - "svdupq_n_b8"