[Serialization] Minor ModuleFile/ModuleFileSharedCore improvements

[rintaro]

• Add properties to ModuleFile that hold some informations from the control block.
• ExtendedValidationInfo parameter for ModuleFileSharedCore::load() cannot be nullptr. Make it non-defaulted Rvalue reference.
• Remove ExtendedValidationInfo parameter from ModuleFileSharedCore::load(). Now that all required information can be fetched from ModuleFile.

[rintaro]

@swift-ci Please smoke test

[akyrtzi]

It's a bit unclear to me why we need the bits accessible from both ModuleFile and ExtendedValidationInfo.
You are replacing the accesses from ExtendedValidationInfo with accesses from ModuleFile but then why do we need them in ExtendedValidationInfo and if we do need them, why add the accessors in ModuleFile and not initialize the ExtendedValidationInfo bits from the Core object?

[rintaro]

These bits are not actually needed in ExtendedValidationInfo because other users don't use them. But when reading OPTIONS_BLOCK inside CONTROL_BLOCK, ExtendedValidationInfo is the only thing to store the informations. So we need to initialize ExtendedValidationInfo first, then read the bits from it to initialize ModuleFileSharedCore.

[rintaro]

Added another commit to remove ExtendedValidationInfo parameter from ModuleFileSharedCore::load(). Any of callers don't use it.

[rintaro]

@swift-ci Please smoke test

[akyrtzi]

Nice improvement to avoid passing ExtendedValidationInfo to so many APIs!
Is ExtendedValidationInfo still usable from other places or can it be moved to implementation detail of ModuleFileSharedCore?

[rintaro]

getSDKPath() and getExtraClangImporterOptions() still has some users which directly call validateControlBlock().