[dynamic] make dynamic failed

[qiaojingx]

Description

This is a regression issue. Build dynamic failed.

Test Code

/modules/Assert.js;
/tests/test-timers.js;

Simple test.js:
runJS('timer.js');

Steps to Reproduction

1. Copy /modules/Assert.js to a101 board as assert.js
2. Copy /tests/test-timers.js to a101 board as timer.js
3. Build simple test.js and flash it to a101 board.
   make dynamic JS=samples/test.js ROM=256

Actual Result

Build failed:

Expected Result

Build dynamic successfully.

Test Builds

Branch	Commit Id	Target Device	Test Date	Result
master	f90d9d1	arduino 101	Jun 12, 2018	Pass
master	2b033e1	arduino 101	Jun 12, 2018	Fail

Additional Information

[qiaojingx]

Verified with commit 2b033e1 + #1889. This issue is fixed.
This issue will be closed after patch #1889 merged.