Dispense with TCGBackendData, as it has never been used for more than
holding a single pointer. Use a define in the cpu/tcg-target.h to
signal requirement for TCGLabelQemuLdst, so that we can drop the no-op
tcg-be-null.h stubs. Rename tcg-be-ldst.h to tcg-ldst.inc.c.
Backports commit 659ef5cbb893872d25e9d95191cc23b16546c8a1 from qemu
Undo the workaround at b17a6d3390f87620735f7efb03bb1c96682ff449.
If there are lots of memory operations in a TB, the slow path code
can exceed the highwater reservation. Add a check within the loop.
Backports commit 23dceda62a3643f734b7aa474fa6052593ae1a70 from qemu
The extra information is not yet used but it is now available.
This requires minor changes through all of the tcg backends.
Backports commit 3972ef6f830d65e9bacbd31257abedc055fd6dc8 from qemu