Force a bootstrap for the --disable-flat-float-array test

The default build procedure is broken in --disable-flat-float-array mode
since PR#2188 was merged.  This commit unblocks temporarily the situation
by using a build with bootstrap for --disable-float-float-array-mode.

tools/ci/inria/other-configs

@@ -24,6 +24,6 @@ main="${mainjob} -j8"
 
 ${main} -conf --disable-native-compiler -no-native
 ${main} -conf --disable-naked-pointers
-${main} -conf --disable-flat-float-array
+${main} -with-bootstrap -conf --disable-flat-float-array
 ${main} -conf --enable-flambda -conf --disable-naked-pointers
 OCAMLRUNPARAM="c=1" ${main}