Revert "[Static Analyzer] BugReporter.cpp:2869: Assertion failed: !RemainingNodes...

Revert "[Static Analyzer] BugReporter.cpp:2869: Assertion failed: !RemainingNodes.empty() && "No error node found in the trimmed graph""

This is making our internal build bot fail because it results in extra warnings being
emitted past what should be sink nodes. (There is actually an example of this in the
updated malloc.c test in the reverted commit.)

I'm working on a patch to fix the original issue by adding a new checker API to explicitly
create error nodes. This API will ensure that error nodes are always tagged in order to
prevent them from being reclaimed.

This reverts commit r246188.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@247103 91177308-0d34-0410-b5e6-96231b3b80d8