Ignore test tmp directories

Attempting to iterate hard over some shell scripts can lead to
frustration when running static analysis. The problem occurs when you
either accidently add a tab to a shell file, or a trailing white space
character. Re-running the shellcheck then picks up the tmp.XXX
directories as you didn't delete them.

Deleting the directories shouldn't be mandatory as you may want to
analise them again in the future. Instead we should tell the checks to
ignore those tmp directories and move along.

tests/suites/static_analysis/lint_shell.sh

@@ -1,5 +1,5 @@
 run_shellcheck() {
-  OUT=$(shellcheck --shell sh tests/*.sh tests/includes/*.sh tests/suites/**/*.sh 2>&1 || true)
+  OUT=$(shellcheck --shell sh tests/main.sh tests/includes/*.sh tests/suites/**/*.sh 2>&1 || true)
   if [ -n "${OUT}" ]; then
     echo ""
     echo "$(red 'Found some issues:')"
@@ -9,7 +9,8 @@ run_shellcheck() {
 }
 
 run_whitespace() {
-  OUT=$(grep -Pr '\t' tests/ | grep '\.sh:' || true)
+  # shellcheck disable=SC2063
+  OUT=$(grep -n -r --include "*.sh" "$(printf '\t')" tests/ | grep -oP "^.*:\d+" || true)
   if [ -n "${OUT}" ]; then
     echo ""
     echo "$(red 'Found some issues:')"
@@ -20,7 +21,8 @@ run_whitespace() {
 }
 
 run_trailing_whitespace() {
-  OUT=$(grep -nr " $" tests/ | grep '\.sh:' || true)
+  # shellcheck disable=SC2063
+  OUT=$(grep -n -r --include "*.sh" " $" tests/ | grep -oP "^.*:\d+" || true)
   if [ -n "${OUT}" ]; then
     echo ""
     echo "$(red 'Found some issues:')"