Suppress more clang-analyzer warnings

[jbytheway]

Summary

None

Purpose of change

These are a handful of false-positive warnings in idl_parser.cpp all of which have the same essential root cause: the analyzer cannot follow the ECHECK logic where an error return from some function causes an early return from the calling function. Thus it assumes some value can be left null or uninitialized when in fact it cannot.

Describe the solution

Suppress the warnings.

Describe alternatives you've considered

Updating clang-tidy?

Testing

Run clang-tidy.

Additional context