[opaque pointer type] Add textual IR support for explicit type parameter to load instruction

Essentially the same as the GEP change in r230786.

A similar migration script can be used to update test cases, though a few more
test case improvements/changes were required this time around: (r229269-r229278)

import fileinput
import sys
import re

pat = re.compile(r"((?:=|:|^)\s*load (?:atomic )?(?:volatile )?(.*?))(| addrspace\(\d+\) *)\*($| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$)")

for line in sys.stdin:
  sys.stdout.write(re.sub(pat, r"\1, \2\3*\4", line))

Reviewers: rafael, dexonsmith, grosser

Differential Revision: http://reviews.llvm.org/D7649

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230794 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/Generic/v-split.ll

@@ -2,8 +2,8 @@
 %f8 = type <8 x float>
 
 define void @test_f8(%f8 *%P, %f8* %Q, %f8 *%S) {
-  %p = load %f8* %P
-  %q = load %f8* %Q
+  %p = load %f8, %f8* %P
+  %q = load %f8, %f8* %Q
   %R = fadd %f8 %p, %q
   store %f8 %R, %f8 *%S
   ret void