[llvm] [BOLT][AArch64] Fixes assertion errors occurred when perf2bolt was executed (PR #83394)

[Ádám Kallai via llvm-commits]

================
@@ -706,8 +706,20 @@ class AArch64MCPlusBuilder : public MCPlusBuilder {
     unsigned ShiftVal = AArch64_AM::getArithShiftValue(OperandExtension);
     AArch64_AM::ShiftExtendType ExtendType =
         AArch64_AM::getArithExtendType(OperandExtension);
-    if (ShiftVal != 2)
-      llvm_unreachable("Failed to match indirect branch! (fragment 2)");
+    if (ShiftVal != 2) {
+      // TODO: handle that case where ShiftVal != 2.
----------------
kaadam wrote:

Thanks for the review. Done.

https://github.com/llvm/llvm-project/pull/83394