[modula2] Implement limited VAR parameter static analysis

[modula2] Implement limited VAR parameter static analysis

This patch implements limited VAR parameter static analysis for pointer
parameters.

gcc/m2/ChangeLog:

	* gm2-compiler/M2SymInit.mod (IsExempt): Remove parameter exemption.
	(CheckIndrX): Call SetupLAlias between lhs and content.
	(trashParam): Re-write.
	(SetVarLRInitialized): Indicate shadow and heap are initialized.
	Call SetupIndr between shadow and heap.
	* gm2-compiler/P2SymBuild.mod: Import
	PutProcedureParameterHeapVars.
	(EndBuildProcedure): Call PutProcedureParameterHeapVars.
	* gm2-compiler/SymbolTable.def (GetParameterHeapVar): New
	procedure function.
	(PutProcedureParameterHeapVars): New procedure function.
	* gm2-compiler/SymbolTable.mod (MakeParameterHeapVar): New
	procedure function.
	(GetParameterHeapVar): New procedure function.
	(PuttParameterHeapVar): New procedure function.
	(PutProcedureParameterHeapVars): New procedure.
	(VarParam): HeapVar new record field.
	(PutVarParam): HeapVar assigned to NulSym.

gcc/testsuite/ChangeLog:

	* gm2/switches/uninit-variable-checking/procedures/fail/testdispose3.mod: New test.
	* gm2/switches/uninit-variable-checking/procedures/fail/testdispose4.mod: New test.
	* gm2/switches/uninit-variable-checking/procedures/pass/testdispose3.mod: New test.
	* gm2/switches/uninit-variable-checking/procedures/pass/testdispose4.mod: New test.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>