image/populate_sdk: Simplify imagetest inclusion and drop dummy class file

Having to include some dummy class is suboptimal and we no longer need to
do this. Also move this check to populate_sdk_base since we then don't
need to include it in toolchains specifically.

(From OE-Core rev: 2ee979ff71d31e497be856ea1443667c6d799d34)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/image.bbclass

@@ -1,8 +1,5 @@
 inherit rootfs_${IMAGE_PKGTYPE}
 
-IMAGETEST ?= "dummy"
-inherit imagetest-${IMAGETEST}
-
 inherit populate_sdk_base
 
 TOOLCHAIN_TARGET_TASK += "${PACKAGE_INSTALL}"

meta/classes/imagetest-dummy.bbclass

@@ -1 +0,0 @@
-# dummy testclass file

meta/classes/populate_sdk_base.bbclass

@@ -1,6 +1,9 @@
 inherit meta toolchain-scripts
 inherit populate_sdk_${IMAGE_PKGTYPE}
 
+IMAGETESTCLASS = "${@oe.utils.ifelse(d.getVar('IMAGETEST'),'imagetest-' + (d.getVar('IMAGETEST') or ""),'')}"
+inherit ${IMAGETESTCLASS}
+
 SDK_DIR = "${WORKDIR}/sdk"
 SDK_OUTPUT = "${SDK_DIR}/image"
 SDK_DEPLOY = "${TMPDIR}/deploy/sdk"

meta/recipes-core/meta/meta-toolchain.bb

@@ -6,5 +6,4 @@ PR = "r7"
 LIC_FILES_CHKSUM = "file://${COREBASE}/LICENSE;md5=3f40d7994397109285ec7b81fdeb3b58 \
                     file://${COREBASE}/meta/COPYING.MIT;md5=3da9cfbcb788c80a0384361b4de20420"
 
-IMAGETEST ?= "dummy"
-inherit populate_sdk imagetest-${IMAGETEST}
+inherit populate_sdk