[compiler-rt][msan] Ignore addrinfo padding in getaddrinfo interceptor (#219124)

Avoid checking padding bytes in `struct addrinfo` in the `getaddrinfo`
interceptor.

The interceptor used a single `COMMON_INTERCEPTOR_READ_RANGE` for the
whole structure, which caused MSan to report uninitialized padding even
when all
named members were initialized.

Check each member separately instead.

Testing
- Added `getaddrinfo-padding.cpp` to cover the padding case
- Verified the new test fails before the fix and passes after the change
- Verified `getaddrinfo-positive.cpp` still reports uninitialized fields
- Ran `ninja -C build/runtimes/runtimes-bins check-msan` on AArch64
Linux

Fixes #162216

GitOrigin-RevId: 29e6b15d01aef1b82b6fc55c723c48b550585a41