Replaced "__asm call $+5" pattern to get the IP with a label.

This was suggested by Kumpera as a work-around for the lack of support for $ in clang-cl.
Revert "Fixed TLAB_ACCESS_INIT usages in MSVC by declaring the variables explicitly at the start of each block."

This will be fixed in a slightly different way.

This reverts commit aa7ab303bae3de8e8401cbbb4dbc92964347994e.
Fixed TLAB_ACCESS_INIT usages in MSVC by moving the macro expansions to the start of each block.