This commit unifies the way auxillary RootScopeModule and DynamicTestModule are compiled in R3TestBed by calling `compileNgModuleDefs` explicitly for RootScopeModule. This change also resolves the problem where TestBed's code was used from the @angular/core NPM package: due to the "jit" flag, the @NgModule decorator on the RootScopeModule was transformed to RootScopeModule.decorators = [...], but actual ngModuleDef was never defined.
PR Close#30037