Cherry-picked merge of D-Programming-Language/druntime#857 from 2.066:

[trivial] Make rt.minfo import in object_.d function-local.

The 2.065 frontend trips over this when building the druntime
tests in shared library mode with LDC (forward reference to the
Object base class of TypeInfo when accessing the latter from
within rt.util.container). No idea why this happens, or why it
doesn't with DMD, but this fixes it and it also is a small
improvement on its own regardless.
Backported D-Programming-Language/druntime#791 from 2.066:
fix for Issue 11543 - multiple definition of std.regex with shared library

The copy relocations for the ModuleInfo symbols generated
by the linker when building the main executable without PIC
enabled were throwing the module collision detection off.
Work around TLS address caching issue with multiplexing fibers across threads.

See: GitHub #666.