[libunwind] Fixed a number of typos

I went over the output of the following mess of a command:

`(ulimit -m 2000000; ulimit -v 2000000; git ls-files -z | parallel --xargs -0 cat | aspell list --mode=none --ignore-case | grep -E '^[A-Za-z][a-z]*$' | sort | uniq -c | sort -n | grep -vE '.{25}' | aspell pipe -W3 | grep : | cut -d' ' -f2 | less)`

and proceeded to spend a few days looking at it to find probable typos
and fixed a few hundred of them in all of the llvm project (note, the
ones I found are not anywhere near all of them, but it seems like a
good start).

Reviewed By: #libunwind, MaskRay

Differential Revision: https://reviews.llvm.org/D130948

NOKEYCHECK=True
GitOrigin-RevId: dad00daa7a0a656640f7579c2c21933ef97a1978
diff --git a/src/UnwindCursor.hpp b/src/UnwindCursor.hpp
index d325ed5..e8b9556 100644
--- a/src/UnwindCursor.hpp
+++ b/src/UnwindCursor.hpp
@@ -510,7 +510,7 @@
   void setDispatcherContext(DISPATCHER_CONTEXT *disp) { _dispContext = *disp; }
 
   // libunwind does not and should not depend on C++ library which means that we
-  // need our own defition of inline placement new.
+  // need our own definition of inline placement new.
   static void *operator new(size_t, UnwindCursor<A, R> *p) { return p; }
 
 private:
@@ -946,7 +946,7 @@
 #endif
 
   // libunwind does not and should not depend on C++ library which means that we
-  // need our own defition of inline placement new.
+  // need our own definition of inline placement new.
   static void *operator new(size_t, UnwindCursor<A, R> *p) { return p; }
 
 private:
@@ -2461,7 +2461,7 @@
                              reinterpret_cast<void *>(pc));
 
   // The return address is the address after call site instruction, so
-  // setting IP to that simualates a return.
+  // setting IP to that simulates a return.
   newRegisters.setIP(reinterpret_cast<uintptr_t>(returnAddress));
 
   // Simulate the step by replacing the register set with the new ones.