support/testing: test_gstreamer1: fix test by using bootlin toolchain

Since Buildroot commit [1], the test_gstreamer1 runtime test is
failing to build the tesseract-ocr package. The root cause is that
the test uses the default arm external toolchain, which is the Linaro
ARM 2018.05 based on gcc 7.3.1.

Since [1], tesseract-orc no longer compiles with gcc 7 (it requires at
least gcc 8).

This commit fixes the issue by switching the toolchain to the
bootlin versions (based on gcc 14 at the time of this commit).

Also, changing the compiler version slightly slowed down the video
encoding. This commit also increases the encoding command timeout.

Fixes:
https://gitlab.com/buildroot.org/buildroot/-/jobs/9407846232

[1] https://gitlab.com/buildroot.org/buildroot/-/commit/f32da8b9844ae5f1b9dc6b7a89d7d9bd9d194f55

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>
(cherry picked from commit 356c70677cd71fbe790b89a6391f41a5bebc4686)

support/testing/tests/package/test_gstreamer1.py

@@ -15,6 +15,7 @@ class TestGstreamer1(infra.basetest.BRTest):
         BR2_cortex_a9=y
         BR2_ARM_ENABLE_VFP=y
         BR2_TOOLCHAIN_EXTERNAL=y
+        BR2_TOOLCHAIN_EXTERNAL_BOOTLIN=y
         BR2_PACKAGE_DEJAVU=y
         BR2_PACKAGE_GSTREAMER1=y
         BR2_PACKAGE_GST1_PLUGINS_BASE=y
@@ -60,7 +61,7 @@ class TestGstreamer1(infra.basetest.BRTest):
             f"timeoverlay text=\"{msg_prefix}\" font-desc=\"Sans, 24\" ! " \
             f"theoraenc ! oggmux ! filesink location={video_file}"
         cmd = f"gst-launch-1.0 -v {enc_pipeline}"
-        self.assertRunOk(cmd)
+        self.assertRunOk(cmd, timeout=15)
 
         # We decode our previous video file and store each frame in a
         # PNG image file.