[lldb][swift] Increase number of Rows inspected when unwinding async functions

We were overly conservatives in our initial estimations: if callee saved
registers are used, they are usually spilled first, increasing the
number of rows in the prologue.

Author: felipepiovezan

lldb/source/Plugins/LanguageRuntime/Swift/SwiftLanguageRuntime.cpp

@@ -2584,8 +2584,8 @@ GetFrameSetupInfo(UnwindPlan &unwind_plan, RegisterContext &regctx) {
   if (!fp_unwind_regdomain)
     return fp_unwind_regdomain.takeError();
 
-  // Look at the first few (4) rows of the plan and store FP's location.
-  const int upper_bound = std::min(4, unwind_plan.GetRowCount());
+  // Look at the first few (8) rows of the plan and store FP's location.
+  const int upper_bound = std::min(8, unwind_plan.GetRowCount());
   llvm::SmallVector<AbstractRegisterLocation, 4> fp_locs;
   for (int row_idx = 0; row_idx < upper_bound; row_idx++) {
     RowSP row = unwind_plan.GetRowAtIndex(row_idx);