support/testing: consistently use raw strings for re.compile

Otherwise Python 3.x flake8 complains with:

W605 invalid escape sequence '\s'

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Reviewed-by: Titouan Christophe <titouan.christophe@railnova.eu>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit b0078c058a4a935083f9494518216a46df20b5af)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

support/testing/infra/__init__.py

@@ -78,7 +78,7 @@ def get_elf_arch_tag(builddir, prefix, fpath, tag):
     cmd = ["host/bin/{}-readelf".format(prefix),
            "-A", os.path.join("target", fpath)]
     out = run_cmd_on_host(builddir, cmd)
-    regexp = re.compile("^  {}: (.*)$".format(tag))
+    regexp = re.compile(r"^  {}: (.*)$".format(tag))
     for line in out.splitlines():
         m = regexp.match(line)
         if not m:
@@ -105,7 +105,7 @@ def get_elf_prog_interpreter(builddir, prefix, fpath):
     cmd = ["host/bin/{}-readelf".format(prefix),
            "-l", os.path.join("target", fpath)]
     out = run_cmd_on_host(builddir, cmd)
-    regexp = re.compile("^ *\[Requesting program interpreter: (.*)\]$")
+    regexp = re.compile(r"^ *\[Requesting program interpreter: (.*)\]$")
     for line in out.splitlines():
         m = regexp.match(line)
         if not m: