[GISel] TreeMatcher: always skip leaves if they don't care

In `GIMatchTreeOpcodePartitioner::applyForPartition()`, the loop over
the possible leaves skip a leaf if the instruction does not care
about the instruction.
When processing the referenced operands in the next loop the same
leaves need to be skipped.

Later, when these leaves are added to all partitions, the bit vector
must be resized first before the bit representing the leaf is set.

This fixes a crash in llvm-tblgen.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D134192