remove qemu tests

that are being transfered to GA in #2758.
This represents a saving of ~25mn of cpu time on TravisCI.

.travis.yml

@@ -69,12 +69,6 @@ matrix:
         - make arminstall
         - make armbuild
 
-    - name: Qemu PPC + Fuzz Test    # ~13mn
-      dist: trusty   # it seems ppc cross-compilation fails on "current"
-      script:
-        - make ppcinstall
-        - make ppcfuzz
-
     # check release number (release/new tag only)
     - name: Tag-Specific Test
       if: tag =~ ^v[0-9]\.[0-9]
@@ -91,19 +85,6 @@ matrix:
         - cat /proc/cpuinfo
         - make -C tests fuzztest
 
-    - name: Qemu PPC64 + Fuzz test  # ~13mn, presumed Big-Endian (?)
-      dist: trusty  # note : PPC64 cross-compilation for Qemu tests seems broken on Xenial
-      script:
-        - make ppcinstall
-        - make ppc64fuzz
-
-    # note : we already have aarch64 tests on hardware
-    - name: Qemu aarch64 + Fuzz Test (on Xenial)    # ~14mn
-      dist: xenial
-      script:
-        - make arminstall
-        - make aarch64fuzz
-
     # This test currently fails on GA specifically, for no obvious reason
     # (it works fine on travisCI, and on local test platforms).
     - name: Versions Compatibility Test   # ~6mn