t9001-send-email.sh: fix expected absolute paths on Windows

t9001-send-email.sh: fix expected absolute paths on Windows

Git for Windows is a native Windows program that works with native
absolute paths in the drive letter style C:\dir. The auxiliary
infrastructure is based on MSYS2, which uses POSIX style /C/dir.

When we test for output of absolute paths produced by git.exe, we
usally have to expect C:\dir style paths. To produce such expected
paths, we have to use $(pwd) in the test scripts; the alternative,
$PWD, produces a POSIX style path. ($PWD is a shell variable, and the
shell is bash, an MSYS2 program, and operates in the POSIX realm.)

There are two recently added tests that were written to expect C:\dir
paths. The output that is tested is produced by `git send-email`, but
behind the scenes, this is a Perl script, which also works in the
POSIX realm and produces /C/dir style output.

In the first test case that is changed here, replace $(pwd) by $PWD
so that the expected path is constructed using /C/dir style.

The second test case sets core.hooksPath to an absolute path. Since
the test script talks to native git.exe, it is supposed to place a
C:/dir style path into the configuration; therefore, keep $(pwd).
When this configuration value is consumed by the Perl script, it is
transformed to /C/dir style by the MSYS2 layer and echoed back in
this form in the error message. Hence, do use $PWD for the expected
value.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>