[llvm-profdata] Reinstate tools/llvm-profdata/malformed-ptr-to-counter-array.test

I removed this test to unblock the ARM bots while looking into failures
(r374915), and am reinstating it now with a fix.

I believe the problem was that counter ptr address I used,
'\0\0\6\0\1\0\0\1', set the high bits of the pointer, not the low bits
like I wanted. On x86_64 this superficially looks like it tests r370826,
but it doesn't, as it would have been caught before r370826. However, on
ARM (or, 32-bit hosts more generally), I suspect the high bits were
cleared, and you get a 'valid' profile.

I verified that setting the *low* bits of the pointer does trigger the
new condition:

-// Note: The CounterPtr here is off-by-one. This should trigger a malformed profile error.
-RUN: printf '\0\0\6\0\1\0\0\1' >> %t.profraw
+// Note: The CounterPtr here is off-by-one.
+//
+// Octal '\11' is 9 in decimal: this should push CounterOffset to 1. As there are two counters,
+// the profile reader should error out.
+RUN: printf '\11\0\6\0\1\0\0\0' >> %t.profraw

This reverts commit c7cf5b3e4b918c9769fd760f28485b8d943ed968.

llvm-svn: 374927