scripts/oe-check-sstate: force build to run for all targets, specifically populate_sysroot

Since the commit "populate_sdk_base/images: Drop use of 'meta' class and
hence do_build dependencies"[1], builds of images or SDKs don't
recursively depend on the top-level do_build target.  This is typically
a good thing: images just depend on the packages themselves and those
dependencies already exist, but they don't need each recipes sysroot to
be populated.

However, eSDK generation is partly done via the script oe-check-sstate,
which does a 'dry-run' build of the target and collates all of the
sstate that is used.  With this commit the sstate that is used is a
fraction of what would be needed in the SDK, specifically there are no
sysroots populated during the build, so there are no sysroots in the
SDK.

This is obviously a problem, as the entire point of an eSDK is to
contain a sysroot.  Resolve this problem by forcing bitbake to run the
build task for all targets, so that all potentially needed sstate is
collated.

[YOCTO #14626]

[1] 41d7f1aa2c

Tested-by: Andrej Valek <andrej.valek@siemens.com>
(From OE-Core rev: 1b62344f919b5122f048b6409d09386d7d6dd3cd)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/oe-check-sstate

@@ -50,7 +50,7 @@ def check(args):
             env['TMPDIR:forcevariable'] = tmpdir
 
         try:
-            cmd = ['bitbake', '--dry-run'] + args.target
+            cmd = ['bitbake', '--dry-run', '--runall=build'] + args.target
             output = subprocess.check_output(cmd, stderr=subprocess.STDOUT, env=env)
 
             task_re = re.compile('NOTE: Running setscene task [0-9]+ of [0-9]+ \(([^)]+)\)')