[lit] Fix c981c53's remaining test fails under windows

For `llvm/utils/lit/tests/shtest-output-printing.py`, the executable
in `%{python}` wasn't properly shell-quoted for windows.  This caused
the 127 exit code mentioned in f254bbf.  Fix quoting and expect
exit code 1 again.

Fix shell-quoting issue in a few more file names in
`llvm/utils/lit/tests/shtest-shell.py`, missed in f254bbf.

Test failures seen in
<https://lab.llvm.org/buildbot/#/builders/216/builds/26436>.

llvm/utils/lit/tests/Inputs/shtest-output-printing/lit.cfg

@@ -2,5 +2,5 @@ import lit.formats
 
 config.name = "shtest-output-printing"
 config.suffixes = [".txt"]
-config.substitutions.append(("%{python}", sys.executable))
+config.substitutions.append(("%{python}", f'"{sys.executable}"'))
 config.test_format = lit.formats.ShTest(execute_external=False)

llvm/utils/lit/tests/shtest-output-printing.py

@@ -8,7 +8,7 @@
 #       CHECK: -- Testing: {{.*}}
 #       CHECK: FAIL: shtest-output-printing :: basic.txt {{.*}}
 #  CHECK-NEXT: ***{{\**}} TEST 'shtest-output-printing :: basic.txt' FAILED ***{{\**}}
-#  CHECK-NEXT: Exit Code: {{[1-9][0-9]*}}
+#  CHECK-NEXT: Exit Code: 1
 # CHECK-EMPTY:
 #  CHECK-NEXT: Command Output (stdout):
 #  CHECK-NEXT: --

llvm/utils/lit/tests/shtest-shell.py

@@ -475,7 +475,7 @@
 # CHECK-NEXT: # executed command: true
 
 #      CHECK: diff -U0 {{.*}}.foo {{.*}}.bar && false || true
-# CHECK-NEXT: diff -U0 {{.*}}.foo {{.*}}.bar
+# CHECK-NEXT: # executed command: diff -U0 {{.+}}.foo{{.*}} {{.+}}.bar{{.*}}
 # CHECK-NEXT: # .---command stdout{{-*}}
 #      CHECK: # | @@ {{.*}} @@
 # CHECK-NEXT: # | -6 foo