[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/upgrade-loop-metadata.ll

@@ -10,7 +10,7 @@ entry:
   br label %for.cond
 
 for.cond:                                         ; preds = %for.inc, %entry
-  %0 = load i32* %i, align 4
+  %0 = load i32, i32* %i, align 4
   %cmp = icmp slt i32 %0, 16
   br i1 %cmp, label %for.body, label %for.end, !llvm.loop !1
 
@@ -18,7 +18,7 @@ for.body:                                         ; preds = %for.cond
   br label %for.inc
 
 for.inc:                                          ; preds = %for.body
-  %1 = load i32* %i, align 4
+  %1 = load i32, i32* %i, align 4
   %inc = add nsw i32 %1, 1
   store i32 %inc, i32* %i, align 4
   br label %for.cond