Revert "Revert "Add testHttpEngine_EnableHttpCache""

This reverts commit eff4a85a4918175e86a44845ec19b24a766b2835.

Reason for revert: Fix silent conflict and reland

Test: m && atest CtsNetHttpTestCases
Change-Id: Iff5c03189aa4fadaa94ad2c1492a9b2e41d749bc
2 files changed