tests/test-clone-pull-corruption

workingctx: correctly compute the flag for noexec filesystems+merge

This bug happens if the filesystem doesn't support exec-bit, during merges,
for example in 24ed7a541f23 on the hg repo.
If f is not in p1, but is in p2 and has the x-bit in p2, since the dirstate is
based on p1, and the FS doesn't support the exec-bit, the dirstate can't
"guess" the right bit.
We instead fix it in workingcontext.flags()/manifest.

#!/bin/sh
#
# Corrupt an hg repo with a pull started during an aborted commit
#

# Create two repos, so that one of them can pull from the other one.
hg init source
cd source
touch foo
hg add foo
hg ci -m 'add foo'
hg clone . ../corrupted
echo >> foo
hg ci -m 'change foo'

# Add a hook to wait 5 seconds and then abort the commit
cd ../corrupted
echo '[hooks]' >> .hg/hgrc
echo 'pretxncommit = sleep 5; exit 1' >> .hg/hgrc

# start a commit...
touch bar
hg add bar
hg ci -m 'add bar' &

# ... and start a pull while the commit is still running
sleep 1
hg pull ../source 2>/dev/null

# see what happened
wait
hg verify