Remove #uses comments from functions: they we're padded out to column 50

Remove #uses comments from functions: they we're padded out to column 50
and were potentially confusing for externally visible functions.

going further, remove the "<i8**> [#uses=3]" comments entirely. They
add a lot of noise, confuse people about what the IR is, and don't add
any particular value.  When the types are long it makes it really really
hard to read IR.

If someone is interested in this sort of thing, the right way to do this
is to implement an AsmAnnotationWriter that produces the same output, and
add a flag to llvm-dis (only) to produce this output.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112894 91177308-0d34-0410-b5e6-96231b3b80d8