t3300-*.sh: Fix a TAP parse error

t3300-*.sh: Fix a TAP parse error

At present, running the t3300-*.sh test on cygwin looks like:

    $ cd t
    $ ./t3300-funny-names.sh
    ok 1 - setup
    # passed all 1 test(s)
    1..1 # SKIP Your filesystem does not allow tabs in filenames
    $

Unfortunately, this is not valid TAP output, which prove notes
as follows:

    $ prove --exec sh t3300-funny-names.sh
    t3300-funny-names.sh .. All 1 subtests passed

    Test Summary Report
    -------------------
    t3300-funny-names.sh (Wstat: 0 Tests: 1 Failed: 0)
      Parse errors: No plan found in TAP output
    Files=1, Tests=1,  2 wallclock secs ( 0.05 usr  0.00 sys +  \
        0.90 cusr  0.49 csys =  1.43 CPU)
    Result: FAIL
    $

This is due to the 'trailing_plan' having a 'skip_directive'
attached to it. This is not allowed by the TAP grammar, which
only allows a 'leading_plan' to be followed by an optional
'skip_directive'. (see perldoc TAP::Parser::Grammar).

A trailing_plan is one that appears in the TAP output after one or
more test status lines (that start 'not '? 'ok ' ...), whereas a
leading_plan must appear before all test status lines (if any).

In practice, this means that the test script cannot contain a use
of the 'skip all' facility:

    skip_all='Some reason to skip *all* tests in this file'
    test_done

after having already executed one or more tests with (for example)
'test_expect_success'. Unfortunately, this is exactly what this
test script is doing. The first 'setup' test is actually used to
determine if the test prerequisite is satisfied by the filesystem
(ie does it allow tabs in filenames?).

In order to fix the parse errors, place the code to determine the
test prerequisite at the top level of the script, prior to the
first test, rather than as a parameter to test_expect_success.
This allows us to correctly use 'skip_all', thus:

    $ ./t3300-funny-names.sh
    # passed all 0 test(s)
    1..0 # SKIP Your filesystem does not allow tabs in filenames
    $

    $ prove --exec sh t3300-funny-names.sh
    t3300-funny-names.sh .. skipped: Your filesystem does not \
        allow tabs in filenames
    Files=1, Tests=0,  2 wallclock secs ( 0.02 usr  0.03 sys +  \
        0.84 cusr  0.41 csys =  1.29 CPU)
    Result: NOTESTS
    $

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>