feat: introduce source maps for templates (#15011)

The main use case for the generated source maps is to give
errors a meaningful context in terms of the original source
that the user wrote.

Related changes that are included in this commit:

* renamed virtual folders used for jit:
  * ng://<module type>/module.ngfactory.js
  * ng://<module type>/<comp type>.ngfactory.js
  * ng://<module type>/<comp type>.html (for inline templates)
* error logging:
  * all errors that happen in templates are logged
    from the place of the nearest element.
  * instead of logging error messages and stacks separately,
    we log the actual error. This is needed so that browsers apply
    source maps to the stack correctly.
  * error type and error is logged as one log entry.

Note that long-stack-trace zone has a bug that 
disables source maps for stack traces,
see https://github.com/angular/zone.js/issues/661.

BREAKING CHANGE:

- DebugNode.source no more returns the source location of a node.  

Closes 14013

packages/compiler/test/output/js_emitter_node_only_spec.ts

@@ -14,9 +14,7 @@ import {ImportResolver} from '@angular/compiler/src/output/path_util';
 import {SourceMap} from '@angular/compiler/src/output/source_map';
 import {ParseLocation, ParseSourceFile, ParseSourceSpan} from '@angular/compiler/src/parse_util';
 
-import {extractSourceMap} from './abstract_emitter_node_only_spec';
-
-const SourceMapConsumer = require('source-map').SourceMapConsumer;
+import {extractSourceMap, originalPositionFor} from './source_map_util';
 
 const someModuleUrl = 'somePackage/somePath';
 
@@ -54,12 +52,11 @@ export function main() {
         const sourceSpan = new ParseSourceSpan(startLocation, endLocation);
         const someVar = o.variable('someVar', null, sourceSpan);
         const sm = emitSourceMap(someVar.toStmt());
-        const smc = new SourceMapConsumer(sm);
 
         expect(sm.sources).toEqual(['in.js']);
         expect(sm.sourcesContent).toEqual([';;;var']);
-        expect(smc.originalPositionFor({line: 1, column: 0}))
-            .toEqual({line: 1, column: 3, source: 'in.js', name: null});
+        expect(originalPositionFor(sm, {line: 1, column: 0}))
+            .toEqual({line: 1, column: 3, source: 'in.js'});
       });
     });
   });