[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/Transforms/IndVarSimplify/phi-uses-value-multiple-times.ll

@@ -13,7 +13,7 @@ entry:
 	br label %bb38.i
 
 bb14.i27:
-	%t0 = load i64* @ue, align 8
+	%t0 = load i64, i64* @ue, align 8
 	%t1 = sub i64 %t0, %i.0.i35
 	%t2 = add i64 %t1, 1
 	br i1 undef, label %bb15.i28, label %bb19.i31