Fix for iterators with const-qualified value type

[danhoeflinger]

Iterator inputs to parallel APIs with a device policy which have a const-qualified value type are experiencing build errors on with MSVC or GCC standard library implementation because of static assertions in the class definition for std::vector.

Our check for USM allocated vector iterators checks all input iterators, and within the check, instantiates a std::vector with a value type which matches the input iterator's value type. Prior to this PR, we do not protect against "ill formed" vector instantiations, like const-qualified, reference, or function types. When the value type of the input iterator are any of these, the build hits std::vector static assertions while attempting to determine if the iterator is a USM allocator std::vector iterator.
This bug was introduced in #1438.

This PR adds a short circuit to avoid such ill-formed std::vector instantiations for specific value types (reference, const, and function types). These will not be USM allocated std::vector iterators, so it should not effect our ability to detect those types.

This fixes the bug reproducer as reported. I have also confirmed that input data processing still works as intended using #1429.

[mmichel11]

LGTM

[danhoeflinger]

This also affects GCC standard library implementation in addition to MSVC. The PR fixes both. Libc++ does not have a static assertion to check constness of value type.

[timmiesmith]

LGTM. Thank you.