Don't inline recursive functions. (#2130)

* Move ProcessFunction* function from pass to the context.

There are a few functions that are used to traverse the call tree.
They currently live in the Pass class, but they have nothing to do with
a pass, and may be needed outside of a pass.  They would be better in
the ir context, or in a specific call tree class if we ever have a need
for it.

* Don't inline recursive functions.

Inlining does not check if a function is recursive or not.  This has
been fine as long as the shader was a Vulkan shader, which forbid
recursive functions.  However, not all shaders are vulkan, so either
we limit inlining to Vulkan shaders or we teach it to look for recursive
functions.

I prefer to keep the passes as general as is reasonable.  The change
does not require much new code in inlining and gives a reason to refactor
some other code.

The changes are to add a member function to the Function class that
checks if that function is recursive or not.

Then this is used in inlining to not inlining a function call if it calls
a recursive function.

* Add id to function analysis

There are a few places that build a map from ids to Function whose
result is that id.  I decided to add an analysis to the context for this
to reduce that code, and simplify some of the functions.

* Add missing file.