[Win32] Set $Config{installsitescript} to a sane value.

Also set $Config{installscript} to match $Config{installsitescript}
Fixes the failing test in:
Perl-Toolchain-Gang/module-build-tiny#35

Author: sisyphus

win32/config.gc

@@ -841,15 +841,15 @@ installman3dir='~INST_TOP~~INST_VER~\man\man3'
 installprefix='~INST_TOP~~INST_VER~'
 installprefixexp='~INST_TOP~~INST_VER~'
 installprivlib='~INST_TOP~~INST_VER~\lib'
-installscript='~INST_TOP~~INST_VER~\bin'
+installscript='~INST_TOP~~INST_VER~\bin~INST_ARCH~'
 installsitearch='~INST_TOP~\site~INST_VER~\lib~INST_ARCH~'
 installsitebin='~INST_TOP~~INST_VER~\bin~INST_ARCH~'
 installsitehtml1dir=''
 installsitehtml3dir=''
 installsitelib='~INST_TOP~\site~INST_VER~\lib'
 installsiteman1dir=''
 installsiteman3dir=''
-installsitescript=''
+installsitescript='~INST_TOP~~INST_VER~\bin~INST_ARCH~'
 installstyle='lib'
 installusrbinperl='undef'
 installvendorarch=''

win32/config.vc

@@ -840,15 +840,15 @@ installman3dir='~INST_TOP~~INST_VER~\man\man3'
 installprefix='~INST_TOP~~INST_VER~'
 installprefixexp='~INST_TOP~~INST_VER~'
 installprivlib='~INST_TOP~~INST_VER~\lib'
-installscript='~INST_TOP~~INST_VER~\bin'
+installscript='~INST_TOP~~INST_VER~\bin~INST_ARCH~'
 installsitearch='~INST_TOP~\site~INST_VER~\lib~INST_ARCH~'
 installsitebin='~INST_TOP~~INST_VER~\bin~INST_ARCH~'
 installsitehtml1dir=''
 installsitehtml3dir=''
 installsitelib='~INST_TOP~\site~INST_VER~\lib'
 installsiteman1dir=''
 installsiteman3dir=''
-installsitescript=''
+installsitescript='~INST_TOP~~INST_VER~\bin~INST_ARCH~'
 installstyle='lib'
 installusrbinperl='undef'
 installvendorarch=''