Mark two coroutine tests as unsupported under ubsan, again

This reverts commit r304580, making bool_await_suspend.pass.cpp and
generator.pass.cpp unsupported on ubsan again. The host compiler is
based on r304329, which has the change from PR33271 (r304277). However,
this was not enough to address the issue.

Bot Failure:
http://lab.llvm.org:8011/builders/libcxx-libcxxabi-x86_64-linux-ubuntu-ubsan/builds/628

Unknown type!
UNREACHABLE executed at /home/eric/full-llvm/llvm/lib/IR/ValueTypes.cpp:287!
llvm::EVT::getEVT(llvm::Type*, bool) (/usr/local/bin/clang-5.0+0x17e7a07)
llvm::TargetLoweringBase::getValueType(llvm::DataLayout const&, llvm::Type*, bool) const (/usr/local/bin/clang-5.0+0x852c4a)
llvm::ComputeValueVTs(llvm::TargetLowering const&, llvm::DataLayout const&, llvm::Type*, llvm::SmallVectorImpl<llvm::EVT>&, llvm::SmallVectorImpl<unsigned long>*, unsigned long) (/usr/local/bin/clang-5.0+0x141b6e9)
 llvm::SelectionDAGBuilder::visitTargetIntrinsic(llvm::CallInst const&, unsigned int) (/usr/local/bin/clang-5.0+0x237b1ca)

clang-5.0: /home/eric/full-llvm/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp:1236: virtual void llvm::DwarfDebug::endFunctionImpl(const llvm::MachineFunction *): Assertion `LScopes.getAbstractScopesList().size() == NumAbstractScopes && "ensureAbstractVariableIsCreated inserted abstract scopes"' failed.
__assert_fail_base /build/glibc-9tT8Do/glibc-2.23/assert/assert.c:92:0
(/lib/x86_64-linux-gnu/libc.so.6+0x2dc82)
llvm::DwarfDebug::endFunctionImpl(llvm::MachineFunction const*) (/usr/local/bin/clang-5.0+0x223f86b)
llvm::DebugHandlerBase::endFunction(llvm::MachineFunction const*) (/usr/local/bin/clang-5.0+0x227a5a1)
llvm::AsmPrinter::EmitFunctionBody() (/usr/local/bin/clang-5.0+0x222522f)

llvm-svn: 304591