Make AndroidRuntime only start the debugger for zygote forked apps.

This got changed unintentionally in commit fffb273. Restore the
original behavior where JDWP will not be enabled for non-zygote apps.

Bug: 72400560
Test: atest CtsJdwpSecurityHostTestCases
Change-Id: I364a9d8b6e87efc1604741a7e5dd68221ed8e491
1 file changed