d: Inline bounds checking for simple array assignments.

d: Inline bounds checking for simple array assignments.

This optimizes the code generation of simple array assignments, inlining
the array bounds checking code so there is no reliance on the library
routine _d_arraycopy(), which also deals with postblit and copy
constructors for non-trivial arrays.

gcc/d/ChangeLog:

	* expr.cc (ExprVisitor::visit (AssignExp *)): Inline bounds checking
	for simple array assignments.

gcc/testsuite/ChangeLog:

	* gdc.dg/array1.d: New test.