Propagate types from symbol to aliases.

This is similar, but not identical to what gas does. The logic in MC is to just
compute the symbol table after parsing the entire file. GAS is mixed, given

.type b, @object
a = b
b:
.type b, @function

It will propagate the change and make 'a' a function. Given

.type b, @object
b:
a = b
.type b, @function

the type of 'a' is still object.

Since we do the computation in the end, we produce a function in both cases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204555 91177308-0d34-0410-b5e6-96231b3b80d8
InstrProf: Check pointer size in raw profile

Since the profile can come from 32-bit machines, we need to check the
pointer size.  Change the magic number to facilitate this.

Adds tests for reading 32-bit and 64-bit binaries (both big- and
little-endian).  The tests write a binary using printf in RUN lines
(like raw-magic-but-no-header.test).  Assuming the bots don't complain,
this seems like a better way forward for testing RawInstrProfReader than
committing binary files.

<rdar://problem/16400648>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204557 91177308-0d34-0410-b5e6-96231b3b80d8