[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/PowerPC/fast-isel-call.ll

@@ -85,7 +85,7 @@ define i32 @bar0(i32 %i) nounwind {
 ;define void @foo3() uwtable {
 ;  %fptr = alloca i32 (i32)*, align 8
 ;  store i32 (i32)* @bar0, i32 (i32)** %fptr, align 8
-;  %1 = load i32 (i32)** %fptr, align 8
+;  %1 = load i32 (i32)*, i32 (i32)** %fptr, align 8
 ;  %call = call i32 %1(i32 0)
 ;  ret void
 ;}