Fix robust buffer access result checking for partially out of bound cases

Fix robust buffer access result checking for partially out of bound cases

The spec says:
Out-of-bounds buffer loads will return any of the following values:
...
Values from anywhere within the memory range(s) bound to the buffer (possibly including bytes of memory past the end of the buffer, up to the end of the bound range).
...

So partially out of bound load may return memory content for the in bound part. E.g., loading a 64-bit value from a buffer with 3B size (allocated 4B size), the first 4B can be value within the buffer.

Affected tests:
dEQP-VK.robustness.buffer_access.through_pointers.*

Change-Id: I1fab8d3819cf4d5935904a1c7762c3660c67379b