COFF: Assign the correct symbol type to internal functions.

COFF: Assign the correct symbol type to internal functions.

The COFFSymbolRef::isFunctionDefinition() function tests for several conditions
that are not related to whether a symbol is a function, but rather whether
the symbol meets the requirements for a function definition auxiliary record,
which excludes certain symbols such as internal functions and undefined
references. The test we need to determine the symbol type is much simpler:
we only need to compare the complex type against IMAGE_SYM_DTYPE_FUNCTION.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244195 91177308-0d34-0410-b5e6-96231b3b80d8