Do not add jacocoagent to framework libraries in static coverage builds.

Framework libraries need special handling in static coverage builds:
they should not have static dependency on jacoco, otherwise there
would be multiple conflicting definitions of the same jacoco classes
coming from different bootclasspath jars.

This CL does two things:

- Move the code that enables instrumentation of framework libraries
  from AndroidGenerateBuildActions phase to the earlier DepsMutator
  phase. This is necessary because DepsMutator phase already does some
  things that depend on the instrumentation flag.

- Explicitely exclude framework libraries from those libraries
  which have static dependency on jacoco.

This CL does not fix any apparent build problems: prior to it the
framework libraries were not excluded properly, but this was masked by
wrong order of checking / setting instrumentation flag.

Note that static coverage builds without framework coverage fail to
boot, namely this build command:

  $ build/soong/soong_ui.bash --make-mode \
    SKIP_ABI_CHECKS=true \
    TARGET_PRODUCT=aosp_walleye TARGET_BUILD_VARIANT=userdebug droid \
    EMMA_INSTRUMENT=true \
    EMMA_INSTRUMENT_STATIC=true \
    NATIVE_COVERAGE=true

..causes the following boot-time errors in logcat:

    01-08 12:31:48.670  1252  1252 E System  : java.lang.StackOverflowError: stack size 8192KB
    01-08 12:31:48.670  1252  1252 E System  :      at org.jacoco.agent.rt.internal.Offline.$jacocoInit(Unknown Source:13)
    01-08 12:31:48.670  1252  1252 E System  :      at org.jacoco.agent.rt.internal.Offline.getProbes(Unknown Source:0)

Also note that static coverage with framework coverage failed to build
prior to CL Iaa198b8505aaff36e6685559642ff721637ce55f (dex2oat failed
to create boot image due to missing classes).

Test: non-static coverage without framework coverage boots:
  $ build/soong/soong_ui.bash --make-mode \
    SKIP_ABI_CHECKS=true \
    TARGET_PRODUCT=aosp_walleye TARGET_BUILD_VARIANT=userdebug droid \
    EMMA_INSTRUMENT=true \
    NATIVE_COVERAGE=true

Test: non-static coverage with framework coverage boots:
  $ build/soong/soong_ui.bash --make-mode \
    SKIP_ABI_CHECKS=true \
    TARGET_PRODUCT=aosp_walleye TARGET_BUILD_VARIANT=userdebug droid \
    EMMA_INSTRUMENT=true \
    EMMA_INSTRUMENT_FRAMEWORK=true \
    NATIVE_COVERAGE=true

Test: static coverage with framework coverage boots:
  $ build/soong/soong_ui.bash --make-mode \
    SKIP_ABI_CHECKS=true \
    TARGET_PRODUCT=aosp_walleye TARGET_BUILD_VARIANT=userdebug droid \
    EMMA_INSTRUMENT=true \
    EMMA_INSTRUMENT_FRAMEWORK=true \
    EMMA_INSTRUMENT_STATIC=true \
    NATIVE_COVERAGE=true

Change-Id: I700f979a5d638ce632f5e8b920b9d0adb3c80248