Missing checks in IR::validateDefinitions

[brianjohnson5972]

Spent a good portion of today tracking down an issue caused by what looks like the data section of the wasm being too large. The attached wast files indicate a valid file and an invalid file. The difference is an extra character in a string literal and it causes the last test to not execute, which is tied to an if check for "testolend" (comparing to passed in code) which is pushed from 9984 to 10000. That would point to that address being outside the valid range, but adding a few more characters can cause "testolstart" code to fail, but adding more characters to string literals doesn't cause other code comparisons to fail, so still not obvious what the error is or what the code would have to look for to identify that the setcode was invalid.

memory_test.wast.hpp.bad.txt
memory_test.wast.hpp.good.txt

[pavybez]

Could it be related to this #425

[brianjohnson5972]

Pull Request #490 fixes this.