selftests/vm: rename run_vmtests --> run_vmtests.sh

Rename to *.sh, in order to match the conventions of all of the other
items in selftest/vm.

The only reason not to use a .sh suffix a shell script like this, might be
to make it look more like a normal program, but that's not an issue here.

Link: https://lkml.kernel.org/r/20201026064021.3545418-4-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/testing/selftests/vm/Makefile

@@ -73,7 +73,7 @@ TEST_GEN_FILES += virtual_address_range
 TEST_GEN_FILES += write_to_hugetlbfs
 endif
 
-TEST_PROGS := run_vmtests
+TEST_PROGS := run_vmtests.sh
 
 TEST_FILES := test_vmalloc.sh