[GR-39982] Disable NEON feature in Sulong toolchain for AArch64

sulong/projects/com.oracle.truffle.llvm.toolchain.launchers/src/com/oracle/truffle/llvm/toolchain/launchers/common/ClangLikeBase.java

@@ -181,6 +181,15 @@ private static List<String> getVectorInstructionSetFlags() {
         switch (Arch.getCurrent()) {
             case X86_64:
                 return Arrays.asList("-mno-sse3", "-mno-avx");
+            case AARCH_64:
+                /*
+                 * This is a bit controversal as per Arm ARM Armv8 has support for "Advanced SIMD"
+                 * (aka. NEON), thus it's a reasonable assumption that `__ARM_NEON` is always
+                 * defined. However, there is an option to ship an Armv8 core without NEON for
+                 * "spezialized markets", so in theory a clean codebase must have a fallback for
+                 * which `__ARM_NEON` is not defined.
+                 */
+                return Arrays.asList("-Xclang", "-target-feature", "-Xclang", "-neon");
             default:
                 return Collections.emptyList();
         }