Add test to make sure LEB fragments are handled correctly.

Author: rastogishubham

llvm/test/CAS/LEB-mccas.ll

@@ -0,0 +1,28 @@
+; This test was reduced using delta and llvm-reduce on a crash in MCCAS because
+; of an FT_LEB fragment which was attempted to be merged into an 
+; MCMergedFragmentRef. If MCCAS behaves correctly, llc should not crash when 
+; trying to create an MCCAS representation of this LLVM IR file.
+
+; RUN: rm -rf %t && mkdir -p %t
+; RUN: llc --filetype=obj --mccas-verify --cas-backend --cas-friendly-debug-info --cas=%t/cas %s -o %t/LEB.o 
+
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-n32:64-S128-Fn32"
+target triple = "arm64-apple-macosx14.0.0"
+
+; Function Attrs: noinline optnone
+define { ptr, i32 } @appendAnimation() #0 personality ptr @__objc_personality_v0 {
+  %1 = invoke ptr null(ptr null, ptr null)
+          to label %2 unwind label %3
+
+2:                                                ; preds = %0
+  ret { ptr, i32 } zeroinitializer
+
+3:                                                ; preds = %0
+  %4 = landingpad { ptr, i32 }
+          catch ptr null
+  ret { ptr, i32 } %4
+}
+
+declare i32 @__objc_personality_v0(...)
+
+attributes #0 = { noinline optnone }