t/t-push-failures-local.sh: align setup steps

Our t/t-push-failures-local.sh test script includes a number of tests
which validate the behaviour of the "git push" command when Git LFS
objects are missing or corrupt.

While these tests are largely similar in their implementation, they
vary in a number of formatting and implementation details unrelated to
the specifics of the different conditions they simulate.  These
variations are artifacts of the evolution of our test suite over time;
for example, the tests in the t/t-push-failures-local.sh script were
refactored and collected from several earlier tests in commit
4d52e08 of PR git-lfs#3109.

In a subsequent commit in this PR we expect to update the Git LFS
client to remove some non-functional code which attempts to recreate
missing Git LFS objects during push operations.  In many cases this
change will cause the client to report missing objects in an earlier
stage of push operations than it does now.  We also expect to reword
the error message the client will output in such cases.

Before we make these changes, we first revise the related tests in our
test suite so they are as simple and similar as possible.  This will
ensure that when we update the Git LFS client we can clearly identify
the changes that we need to make in our tests to accommodate the
client's new behaviour.

A pair of tests in the t/t-push-failures-local.sh script, specifically
the "push reject missing objects (lfs.allowincompletepush default)" and
"push reject corrupt objects (lfs.allowincompletepush default)" tests,
perform their setup of Git LFS objects and Git commits in a different
sequence than the other tests in the same script.

In order to align the code in all these tests as closely as possible,
we simply revise the setup steps of the last two tests in the
t/t-push-failures-local.sh script so they follow the same pattern
as those of the other tests.  This change has no functional effect;
the only notable detail is that the tests now create all their Git LFS
objects in a single commit instead of using a separate commit to create
each object.

Author: chrisd8088

t/t-push-failures-local.sh

@@ -101,17 +101,16 @@ begin_test "push reject missing objects (lfs.allowincompletepush default)"
   git add .gitattributes
   git commit -m "initial commit"
 
+  present="present"
+  present_oid="$(calc_oid "$present")"
+  printf "%s" "$present" > present.dat
+
   missing="missing"
   missing_oid="$(calc_oid "$missing")"
   printf "%s" "$missing" > missing.dat
-  git add missing.dat
-  git commit -m "add missing.dat"
 
-  present="present"
-  present_oid="$(calc_oid "$present")"
-  printf "%s" "$present" > present.dat
-  git add present.dat
-  git commit -m "add present.dat"
+  git add missing.dat present.dat
+  git commit -m "add objects"
 
   delete_local_object "$missing_oid"
 
@@ -141,17 +140,16 @@ begin_test "push reject corrupt objects (lfs.allowincompletepush default)"
   git add .gitattributes
   git commit -m "initial commit"
 
+  present="present"
+  present_oid="$(calc_oid "$present")"
+  printf "%s" "$present" > present.dat
+
   corrupt="corrupt"
   corrupt_oid="$(calc_oid "$corrupt")"
   printf "%s" "$corrupt" > corrupt.dat
-  git add corrupt.dat
-  git commit -m "add corrupt.dat"
 
-  present="present"
-  present_oid="$(calc_oid "$present")"
-  printf "%s" "$present" > present.dat
-  git add present.dat
-  git commit -m "add present.dat"
+  git add corrupt.dat present.dat
+  git commit -m "add objects"
 
   corrupt_local_object "$corrupt_oid"