Perl_croak->Perl_croak_nocontext in core typemap + win32 static gitignore

-1 less asm op for every very rarely executed branch on threaded perl
-add a build product to ignore on the rarely tested Win32 static perl build
SvREFCNT_dec_NN in SDBM

VC 2003 optimizer didn't catch it because SvREFCNT_dec is rarely inlined
on -O1
Ignore proxies in HTTP::Tiny tests

I have HTTP_PROXY and http_proxy set.  HTTP::Tiny just gained
HTTP_PROXY capabilities, and all the tests fail, because they were
only masking http_proxy, not HTTP_PROXY.

Reported at https://github.com/chansen/p5-http-tiny/issues/60.