Fix opt-remark with hotness testcase for sample-based PGO

1. Require hotness on all remark lines with -verify.

3. Fix the samplePGO file to actually produce hotness on each line.

The second remark has hotness 60 rather 30 which I don't quite understand but
testing this is strictly better than before.  It also unblocks the commit of
D40678.

llvm-svn: 319577