[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/Bitcode/function-encoding-rel-operands.ll

@@ -44,7 +44,7 @@ define double @test_float_binops(i32 %a) nounwind {
 define i1 @test_load(i32 %a, {i32, i32}* %ptr) nounwind {
 entry:
   %0 = getelementptr inbounds {i32, i32}, {i32, i32}* %ptr, i32 %a, i32 0
-  %1 = load i32* %0
+  %1 = load i32, i32* %0
   %2 = icmp eq i32 %1, %a
   ret i1 %2
 }