consider multiple uses of heap object

[Qcloud1223]

Solve problem described in #1289.

Sometimes a return value of heap allocation has multiple uses. We need to find out the one right next to it, and make sure it is a bitcast operation. This requires performing a scan over all uses and find out the last one, which corresponds to the first use in human readable IR.

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (0008685) 64.47% compared to head (9122f3d) 64.47%.
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1293   +/-   ##
=======================================
  Coverage   64.47%   64.47%           
=======================================
  Files         223      223           
  Lines       23831    23833    +2     
=======================================
+ Hits        15364    15366    +2     
  Misses       8467     8467           

Files	Coverage Δ
svf-llvm/include/SVF-LLVM/LLVMUtil.h	73.68% <ø> (ø)
svf-llvm/lib/LLVMModule.cpp	82.66% <ø> (ø)
svf-llvm/lib/SVFIRBuilder.cpp	78.28% <100.00%> (ø)
svf-llvm/lib/LLVMUtil.cpp	75.83% <83.33%> (+0.09%)	⬆️
svf-llvm/lib/SymbolTableBuilder.cpp	86.48% <50.00%> (ø)