https://swiftshader-review.googlesource.com/c/SwiftShader/+/43693 added an assert to SpirvShader::Operand that checks the object is a constant or an intermediate.

SpirvShader::Impl::Debugger::exposeVariable() was constructing an Operand for pointer object types (but was not using it), firing this assert.

Bug: b/129000021
Bug: b/148401179
Change-Id: Id22a92e28b1bb16781b98979d26180b1c022db96
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/44014
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Ben Clayton <bclayton@google.com>