[ExceptionDemo] Transition example from MCJIT to ORC and fix compiling errors

[epitavy]

This is a follow up on PR #69485 . I squashed all the previous commit of the PR.
In addition, this fixes an error in the log of the execution. The caught exception type was computed based on a pointer offset, which was in bytes instead of ptr size .
Fixes #63702

[epitavy]

From the comments in the file we can read

llvm-project/llvm/examples/ExceptionDemo/ExceptionDemo.cpp

Lines 9 to 43 in e0a293d

	// Demo program which implements an example LLVM exception implementation, and
	// shows several test cases including the handling of foreign exceptions.
	// It is run with type info types arguments to throw. A test will
	// be run for each given type info type. While type info types with the value
	// of -1 will trigger a foreign C++ exception to be thrown; type info types
	// <= 6 and >= 1 will cause the associated generated exceptions to be thrown
	// and caught by generated test functions; and type info types > 6
	// will result in exceptions which pass through to the test harness. All other
	// type info types are not supported and could cause a crash. In all cases,
	// the "finally" blocks of every generated test functions will executed
	// regardless of whether or not that test function ignores or catches the
	// thrown exception.
	//
	// examples:
	//
	// ExceptionDemo
	//
	// causes a usage to be printed to stderr
	//
	// ExceptionDemo 2 3 7 -1
	//
	// results in the following cases:
	// - Value 2 causes an exception with a type info type of 2 to be
	// thrown and caught by an inner generated test function.
	// - Value 3 causes an exception with a type info type of 3 to be
	// thrown and caught by an outer generated test function.
	// - Value 7 causes an exception with a type info type of 7 to be
	// thrown and NOT be caught by any generated function.
	// - Value -1 causes a foreign C++ exception to be thrown and not be
	// caught by any generated function
	//
	// Cases -1 and 7 are caught by a C++ test harness where the validity of
	// of a C++ catch(...) clause catching a generated exception with a
	// type info type of 7 is explained by: example in rules 1.6.4 in
	// http://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html (v1.22)

Here the result of the execution, which I think is correct.

./bin/ExceptionDemo 2 3 7 -1

Begin Test:

Gen: About to throw exception type <2> in throwFunct.
Gen: Exception type <2> received (stack unwound)  in innerCatchFunct.
Gen: Executing catch block typeInfo2 in innerCatchFunct
Gen: Executing finally block finally in innerCatchFunct
Gen: In end block: exiting in innerCatchFunct.
Gen: No exception in outerCatchFunct!
Gen: Executing finally block finally in outerCatchFunct
Gen: In end block: exiting in outerCatchFunct.

Gen: About to throw exception type <3> in throwFunct.
Gen: Exception type <3> received (stack unwound)  in innerCatchFunct.
Gen: Executing finally block finally in innerCatchFunct
Gen: Exception type <3> received (stack unwound)  in outerCatchFunct.
Gen: Executing catch block typeInfo3 in outerCatchFunct
Gen: Executing finally block finally in outerCatchFunct
Gen: In end block: exiting in outerCatchFunct.

Gen: About to throw exception type <7> in throwFunct.
Gen: Exception type <7> received (stack unwound)  in innerCatchFunct.
Gen: Executing finally block finally in innerCatchFunct
Gen: Exception type <7> received (stack unwound)  in outerCatchFunct.
Gen: Executing finally block finally in outerCatchFunct

runExceptionThrow(...):In C++ catch all.

Gen: About to throw exception type <-1> in throwFunct.
Gen: Foreign exception received.
Gen: Executing finally block finally in innerCatchFunct
Gen: Foreign exception received.
Gen: Executing finally block finally in outerCatchFunct

runExceptionThrow(...):In C++ catch OurCppRunException with reason: thrown by throwCppException(...).

End Test: