[RemoveDIs][DebugInfo] Create overloads of debug intrinsic utilities for DPValues (#78313)
In preparation for the major chunk of the assignment tracking
implementation, this patch adds a new set of overloaded versions of
existing functions that take DbgVariableIntrinsics, with the overloads
taking DPValues. This is used specifically to allow us to use generic code
to handle both DbgVariableIntrinsics and DPValues, reducing code
duplication. This patch doesn't actually add the uses of these functions.