Revert slurp_image extraction for svg_load

* src/image.c (svg_load): Inline slurp_image code again, as it didn't
build in its current form.
Reported by Andreas Schwab <schwab@linux-m68k.org>.
10 jobs for master in 117 minutes and 4 seconds (queued for 8 seconds)
Status Job ID Name Coverage
  Build Images
failed #75098
build-image-inotify

00:05:00

 
  Normal
skipped #75099
test-all-inotify
 
  Platform Images
failed #75100
build-image-eglot

00:04:23

failed #75102
build-image-gnustep

00:04:18

failed #75101
build-image-tree-sitter

01:56:59

 
  Platforms
skipped #75103
test-eglot
skipped #75105
test-gnustep
skipped #75104
test-tree-sitter
 
  Native Comp Images
failed #75106
build-native-comp-speed2

01:56:54

 
  Native Comp
skipped #75107
test-native-comp-speed2
 
Name Stage Failure
failed
build-native-comp-speed2 Native Comp Images There has been a timeout failure or the job got stuck. Check your timeout limits or try again
#12 1222. TZ=UTC0 touch -t 197001010000 emacs-lisp/loaddefs-gen.elc
#12 1222. ELC emacs-lisp/radix-tree.elc
#12 1227. TZ=UTC0 touch -t 197001010000 emacs-lisp/comp.elc
#12 1237. TZ=UTC0 touch -t 197001010000 emacs-lisp/radix-tree.elc
#12 1237. make[4]: Leaving directory '/checkout/lisp'
#12 1237. make -C ../lisp compile-first EMACS="../src/bootstrap-emacs"
#12 1237. make[4]: Entering directory '/checkout/lisp'
#12 1237. ELC+ELN emacs-lisp/macroexp.elc
#12 1237. ELC+ELN emacs-lisp/cconv.elc
#12 1278. ELC+ELN emacs-lisp/byte-opt.elc
failed
build-image-tree-sitter Platform Images There has been a timeout failure or the job got stuck. Check your timeout limits or try again
#12 1574. make -C ../admin/grammars all EMACS="../../src/emacs"
#12 1574. make[4]: Entering directory '/checkout/admin/grammars'
#12 1574. make[4]: Nothing to be done for 'all'.
#12 1574. make[4]: Leaving directory '/checkout/admin/grammars'
#12 1575. make[4]: Entering directory '/checkout/lisp'
#12 1575. ELC emacs-lisp/eieio.elc
#12 1576. ELC emacs-lisp/eieio-base.elc
#12 1577. ELC cedet/semantic/db.elc
#12 1579. ELC international/ja-dic-cnv.elc
#12 1580. ELC org/ox.elc
failed
build-image-inotify Build Images
Error response from daemon: Get "https://emba.gnu.org:5050/v2/": Get "https://emba.gnu.org//jwt/auth?account=gitlab-ci-token&client_id=docker&offline_token=true&service=container_registry": net/http: request canceled (Client.Timeout exceeded while awaiting headers) (Client.Timeout exceeded while awaiting headers)
Running after_script
Running after script...
$ test -n "$(docker ps -aq -f name=${test_name})" && docker cp ${test_name}:checkout/test ${test_name}
$ test -n "$(docker ps -aq -f name=${test_name})" && docker rm ${test_name}
$ find ${test_name} ! \( -name "*.log" -o -name ${EMACS_TEST_JUNIT_REPORT} \) -type f -delete
find: build-image-inotify-505c8062: No such file or directory
Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1

failed
build-image-gnustep Platform Images
 > [internal] load build context:
------
rpc error: code = Unavailable desc = transport is closing
Running after script...
$ test -n "$(docker ps -aq -f name=${test_name})" && docker cp ${test_name}:checkout/test ${test_name}
$ test -n "$(docker ps -aq -f name=${test_name})" && docker rm ${test_name}
$ find ${test_name} ! \( -name "*.log" -o -name ${EMACS_TEST_JUNIT_REPORT} \) -type f -delete
find: build-image-gnustep-505c8062: No such file or directory
ERROR: Job failed: exit code 1
failed
build-image-eglot Platform Images
 > [internal] load build context:
------
rpc error: code = Unavailable desc = transport is closing
Running after script...
$ test -n "$(docker ps -aq -f name=${test_name})" && docker cp ${test_name}:checkout/test ${test_name}
$ test -n "$(docker ps -aq -f name=${test_name})" && docker rm ${test_name}
$ find ${test_name} ! \( -name "*.log" -o -name ${EMACS_TEST_JUNIT_REPORT} \) -type f -delete
find: build-image-eglot-505c8062: No such file or directory
ERROR: Job failed: exit code 1