ICC workarounds for missing alignas

ifdef alignas away for ICC. For MIC::VectorAlignedBaseT we actually use
__attribute__((align(64))), though.

Signed-off-by: Matthias Kretz <kretz@kde.org>
simdarray: declare internal_data(simdarray)

GCC/clang didn't need this, but ICC refuses to compile without it.

Signed-off-by: Matthias Kretz <kretz@kde.org>
tests: Use Vector::IndexType for the frexp parameter

Signed-off-by: Matthias Kretz <kretz@kde.org>
MIC: declare the "standard" member types

Signed-off-by: Matthias Kretz <kretz@kde.org>