[DebugInfo] Add DW_ATE_complex_float case to assert in isUnsignedDIType
Without this patch a `DW_ATE_complex_float` encoding trips an assertion in
`DebugHandlerBase::isUnsignedDIType` with the message `"Unsupported
encoding"`.
By adding a case to the `assert` for `DW_ATE_complex_float` it becomes
supported, behaving in the same way as the already supported `DW_ATE_float`
type (return false).
Note: For the reported reproducer:
#include <complex.h>
int main() {
long double complex r1;
}
The assertion isn't tripped without assignment tracking because instcombine
deletes everything, including the `dbg.declare`, without recovering any
location information. Whereas with assignment tracking we track a zeroing
memset that is emitted by clang.
Reviewed By: probinson
Differential Revision: https://reviews.llvm.org/D151795