Fix assertion when kernel has (illegal) anonymous-typed usrData.

If a foreach kernel has a usrData argument of type pointer to anonymous
struct, we were getting an assertion.  This change fixes the error
handling to match that of similar situations where we illegally have an
anonymous struct type -- we produce an actual error diagnostic.

Test: aosp_angler-eng slang/lit-tests, slang/tests, RsTest (32-bit, 64-bit)

Bug: 62136495
Change-Id: I621f2efccd0b992910de43d2174d02d5fb6d98e0
4 files changed